Skull Thickening

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► [Expansion of calvaria and/or skull base, often associated with sclerosis]

Skull thickening is an aspecific diagnostic sign that occurs in a number of congenital and acquired disorders. However, proper evaluation both of the pattern of skull thickening (focal or widespread, isolated or associated with osteosclerosis and hyperostosis) and of the distribution of lesions (calvaria, skull base, facial bones, or a combination of these) may provide insights allowing the recognition of specific disorders. For diagnostic purposes, it is important to es tablish whether or not the remainder of the skeleton is involved and to define type and extent of the associated lesions. One useful way to classify the sclerosing bone disorders is to divide them into (1) osteoscleroses, i.e., conditions with increased bone density in the absence of significant changes in bony contour (osteopetrosis, pyknodysostosis, benign osteosclerosis of infancy); (2) craniotubular dysplasias, i. e., conditions with increased skull density and abnormal modeling of the long bones (cranio-metaphyseal dysplasia, craniodiaphyseal dysplasia, Pyle disease, frontometaphyseal dysplasia, Melnick-Needles syndrome, dysosteosclerosis, oculo-dento-osseous dysplasia, osteopathia striata with cranial sclerosis); and (3) craniotubular hyperostoses, i.e., conditions with increased bone density and cortical thickening (van Buchem and Worth type of endosteal hyperostosis, sclerosteosis, Camurati-Engelmann disease, hyperphosphatasia) (Kozlowski and Beighton 1995). In the current section, emphasis is given to the distribution of the sclerosing process within the skull, whether involving predominantly the calvari-um, skull base, or a combination of the two, and placing the genetic syndromes and skeletal dysplasias in perspective. Infantile cortical hyperostosis is described under a separate heading because of the selective involvement of the mandible in this disease. It may be worth noting that, given the extensive overlapping of cranial manifestations between different disorders and variable expression of individual diseases, the system of subdivisions adopted here is only useful if it is borne in mind that many disorders do not fit neatly into either category.

Predominant Involvement of the Calvarium. While basal thickening can occur without significant involvement of the calvarium, the converse rarely occurs. Focal thickening and sclerosis of the calvarium may be seen in association with osteoblastic metastases, meningioma, osteoma (Fig. 1.24), fibrous dysplasia, Paget disease, doughnut lesions, cephalohematoma, ossified subdural hematoma, chronic osteomyelitis and, less frequently, arteriovenous malformation of dura, lymphoma, healing histiocytosis X, ischemic necrosis, osteoblastoma, osteochondroma, osteosar-coma, radiation therapy, tuberous sclerosis, and neu-rofibromatosis (Reeder 1993). Diffuse thickening and sclerosis occur in some congenital syndromes (see further discussion), fibrous dysplasia, Paget disease, treated hyperparathyroidism and hypo-thyroidism, hypervitaminosis D, cyanotic congenital heart disease, fluorosis, and in response to decreased intracranial pressure such as is seen in cere-

Inion Osteoma

Fig. 1.24 a, b. Osteoma in an adult male patient. a Lateral view the external surface of the skull in the temporoparietal area. of the skull and b frontal tomogram at the level of the lesion. The lesion is well circumscribed, with smooth margins Note the large, homogeneous mass of dense bone arising from

Fig. 1.24 a, b. Osteoma in an adult male patient. a Lateral view the external surface of the skull in the temporoparietal area. of the skull and b frontal tomogram at the level of the lesion. The lesion is well circumscribed, with smooth margins Note the large, homogeneous mass of dense bone arising from

Wormian Bone
Fig. 1.25. Hyperostosis frontalis interna in a woman patient. Note typical nodular thickening of the inner table of the frontal bones

bral atrophy and shunted hydrocephalus. The disorders in which thickening of the calvaria occurs in association with a radiating trabecular pattern of bone rarefaction (hair-on-end appearance) rather than bone sclerosis,such as hematological disorders (sickle cell anemia, thalassemia, polycythemia) and neoplasms (osteoblastic metastases, neuroblastoma metastases, leukemia, lymphoma, meningioma) are not detailed further. Hyperostosis frontalis interna (Morgagni-Stewart-Morel syndrome, OMIM 144800), a disorder affecting mainly females, is marked by thickening of the inner table of the frontal bones and, occasionally, by obesity and hypertrichosis (Fig. 1.25). The inheritance is uncertain, either an autosomal or an X-linked dominant pattern being possible (Knies and Le Fèvre 1941; Rosatti 1972). No case of male-to-male transmission is known. Elevated serum alkaline phosphatase levels are found in many instances. Galactorrhea seems to be consistently associated (Gegick et al. 1973; Pawlikowski and Komorowski 1983). Calvarial hyperostosis, familial (OMIM 302030) is an X-linked recessive benign condition characterized by thickening of the basifrontal and supra-occipital regions. The cranial base, maxilla, and mandible are spared. All other bones are unaffected (Pagon et al. 1986). Calvarial doughnut lesions, familial (OMIM 126550) are recognized as a rare autosomal dominant disorder characterized by multiple round calvarial radiolucencies surrounded by dense rings of sclerotic bone resembling doughnuts. Additional features include generalized osteoporosis with bone fragility, diaphyseal undermodeling of bones, and multiple dentigerous cysts, with fibrous tissue cysts surrounding the roots of teeth. Serum alkaline phosphatase levels are elevated (Keats and Holt 1969; Baumgartner et al. 2001). In frontometa-physeal dysplasia (OMIM 305620) a thick, torus-like outgrowth of the supraorbital ridge of the frontal bones is characteristic (Lischi 1967). The frontal sinuses are absent. Additional findings include mandibular hypoplasia, dental abnormalities, mild sclerosis of the calvaria and skull base involving the middle ear and cochlea (internal auditory canal and facial nerve canal are spared), and cervical anomalies (absent posterior arch of the atlas, anterior dislocation of the odontoid, fusion between C-2 and C-3) (Holt et al. 1972). Osteosclerosis syndrome, Stanescu type (OMIM 122900) is characterized by short stature, hypoplastic malar bones, prognathism, long thorax, absent pneumatization of frontal and sphenoid bones, and cortical thickening of the long bones, with medullary stenosis (Stanescu et al. 1963; Horovitz et al. 1995). The skull is brachycephalic, with prominent forehead. On roentgenograms it appears dense, with depressed frontoparietal and occipi-toparietal sutures, shallow sella turcica, and deficient sinus development. Wormian bones and calcification of the falx are common. The mandible has an open (obtuse) angle that causes relative prognathism. There is ocular hypertelorism, shallow palate, and malpositioned teeth with poor enamel formation and susceptibility to caries. In cleidocranial dysplasia (OMIM 119600) the skull is large and brachycephalic with biparietal bossing. The fontanels and sutures are wide and late in closing, and multiple wormian bones form within the suture lines. There is segmental calvarial thickening, with involvement of the supraorbital portion of the frontal bone, the squama of the temporal bones, and the occipital bone above the inion (Gorlin et al. 2001). Paranasal sinuses and mastoids are often underdeveloped or absent. Hy-poplasia of the facial bones, increased mandibular length with prognathism, and wide foramen magnum with posterior defects are additional skull features (Jensen 1994). Several defects of dentition are recognized, including supernumerary teeth, crown and root abnormalities, tooth impaction, and lack of tooth eruption (Richardson and Deussen 1994). In Cockayne syndrome (OMIM 216400,216411) there is marked thickening of the calvaria, most pronounced in the frontal and parieto-occipital regions, microcephaly with frontal bossing, intracranial calcification, small sella turcica, small mandible, hypoplastic sinuses and mastoids, and dental abnormalities. The remainder of the skeleton has a slim, osteoporotic appearance. Fountain syndrome (OMIM 229120)

Ultrasonic Osteoporosis
Fig. 1.26. Meningioma in an adult male. Plain film obtained after surgical removal of a large meningioma of the cribriform plate and planum sphenoidale, showing a densely calcified intracranial mass representing either a tumoral remnant or reactive focal hyperostosis

comprises coarse facies with facial edema similar to that seen in the Melkersson-Rosenthal syndrome (OMIM 155900) and progressive granulomatous swelling of the lips, swelling of subcutaneous tissue, mental retardation, sensorineural hearing loss, and marked thickening of the calvaria. The hands are short and stubby, with broad terminal phalanges. Inheritance is assumed to be autosomal recessive (Fountain 1974; Fryns 1989).

Predominant Involvement of the Skull Base. A variety of conditions can cause localized basal thickening and sclerosis, including fibrous dysplasia, chronic mastoiditis, meningioma (Fig. 1.26) and, less commonly, chondrosarcoma, chordoma of clivus, lymphoma, metastasis, osteoma or chondroma, chronic naso-pharyngeal infection, chronic petrositis or osteomyelitis, radiation therapy, sarcoma, sphenoid sinusitis, and mucocele (Reeder 1993). Generalized increase in density and thickness of the skull base is seen in fibrous dysplasia, Paget disease, anemias, fluorosis, hypothyroidism, hyperparathyroidism, hypervitaminosis D, idiopathic hypercalcemia, healing rickets, and some syndromes. As discussed in the previous section, craniometadiaphyseal dysplasia, wormian bone type (OMIM 269300) is characterized by mild sclerosis of the skull base, maxilla, and mandible, frontal bossing, multiple wormian bones, and undermodeled tubular bones (Langer et al. 1991). In pyknodysostosis (Maroteaux-Lamy disease,

Wormian Bones HypothyroidismCraniotubular Dysplasias

Fig. 1.27 a-c. Fibrous dysplasia. a In a 16-year-old male youth note marked thickening and sclerosis of the skull base, most pronounced in the frontal area and anterior cranial fossa. The sphenoid sinuses are completely obliterated by the hyperostotic process. Note expansion of the outer frontal and occipital tables, with relative preservation of the inner table. Small areas of radiolucency are mixed together with the sclerotic process. b, c In a 38-year-old man with the polyostotic form of fibrous dysplasia observe extensive but asymmetrical cal-varial and skull base hyperostosis with prominent involvement of the sphenoid bones. The sclerosing process involves asymmetrically also the facial bones. Note prominence of the external occipital protuberance, a stigma of fibrous dys-plasia

OMIM 265800) the skull is dolichocephalic, with frontal and occipital bossing. Sclerosis involves predominantly the skull base, whereas the calvarial bones are thin, dense, and devoid of diploic markings. The fontanels and cranial sutures are wide open, and multiple wormian bones are commonly present (Edelson et al. 1992). The frontal sinuses and, less often, other paranasal sinuses are absent. The mastoid cells are underpneumatized. The mandible is sclerotic, with absence of the mandibular angle (Bennani-Smires et al. 1984). Lenz-Majewski syndrome (OMIM 151050) is characterized by a large head with wide fontanels and sutures, progressive sclerosis of the skull (especially at the base), facial bones, mandible, and vertebrae; diaphyseal hyperos-tosis; proximal symphalangism; enamel hypoplasia; loose skin; characteristic facies; and mental retarda tion (Gorlin and Whitley 1983). The paranasal sinuses are obliterated, as are the lacrimal ducts, but cranial nerve impairment does not occur. In the autosomal dominant osteopathia striata with cranial sclerosis (Voorhoeve disease, OMIM 166500) there is marked sclerosis of the skull base, with prominent involvement of petrous bones, and thickening of the cranial vault. The sinuses are diminished or entirely obliterated, as are mastoid air cells. The nasal cavity may also be obstructed. The biparietal cranial diameter is usually increased, and there is frontal bossing (Meseguer et al. 1997). Ankylosis of the temporo-mandibular joint has been described (Behninger and Rott 2000). Cranial nerve compromise is common, although it is uncertain whether it is due to narrowed cranial foramina or to other factors, notably vascular problems (Konig et al. 1996). Vertical striations in the

Morgagni Stewart Morel Syndrome

Fig. 1.28 a,b. Craniometaphyseal dysplasia in a 14-year-old boy. Sclerosis involves both the skull base and calvarium, especially in the occipital region. Involvement of the facial bones has resulted in obliteration of the paranasal sinuses. Note orbital hypertelorism

Fig. 1.28 a,b. Craniometaphyseal dysplasia in a 14-year-old boy. Sclerosis involves both the skull base and calvarium, especially in the occipital region. Involvement of the facial bones has resulted in obliteration of the paranasal sinuses. Note orbital hypertelorism metaphyses of the long bones and pelvis are typical features. In Melnick-Needles syndrome (osteodys-plasty, OMIM 309350) cranial features include sclerosis of skull base and mastoids, increased calvarial convolutional markings, delayed closure of the anterior fontanel, underdeveloped paranasal sinuses, small mandible with hypoplasia of the coronoid process, and wide angle and thinning of the mandibular rami, giving a loculated appearance on radiograms (Eggli et al. 1992). The S-shaped appearance of tibiae and radii is a striking skeletal feature. The skull can be involved with either the monostotic (10-25%) or the polyostotic (50%) form of fibrous dysplasia (Jaffe-Lichtenstein disease, OMIM 174800). Common sites include the frontal calvaria, sphenoid, maxillary, and ethmoid bones. Asymmetry and deformation of the head and face may become clinically apparent, and various neurological complications, including cranial palsies and displacement of the ocular globe, may occur (Sharma et al. 2002). On roent-genograms, thickening and sclerosis of the frontal bones, anterior skull base, and facial bones are usually seen to alternate with multiple radiolucent lesions, giving rise to the typical mixed sclerotic and lytic pattern. Widening of the diploic spaces and bony expansion typically occur in an outward direction, thus resulting in external bulging of the outer table. Occasionally, the pattern of skull involvement is one of extensive thickening and sclerosis of the skull base and sphenoid wings (Fig. 1.27a-c), a pattern shared with

Paget disease. A point of difference from Paget disease and neurofibromatosis is that prominent involvement of the facial bones is particularly characteristic in fibrous dysplasia. Furthermore, the inner and outer tables may be thinned, but usually remain essentially intact, whereas in Paget disease they are frequently violated or destroyed (Feldman 1995).

Mixed Pattern of Calvarial and Skull Base Involvement. In craniometaphyseal dysplasia (OMIM 123000,218400), hyperostosis and sclerosis involve the cranial vault (especially the frontal and occipital regions), skull base and, in some cases only, mandible and facial bones. Bony overgrowth and sclerosis of the skull base cause variable compression of cranial nerves VII and VIII, resulting in peripheral facial nerve palsy and vertigo (Beighton et al. 1979). Bony encroachment on the optic foramen may result in optic atrophy and visual loss. Involvement of the otic capsule and tympanic cavity causes sensorineural, conductive, or mixed hearing loss, a symptom becoming apparent in childhood in 50% of cases and progressing slowly in the ensuing years until the zenith is reached by the fourth decade (Kietzer and Paparella 1969). Increased bone deposition produces obliteration of the paranasal sinuses, underpneumatization of mastoid cells, and narrowing of the nasal cavity (Fig. 1.28a,b). The last has its clinical counterpart in the characteristic thick bony wedge that extends laterally over the bridge of the nose and glabella to the zygomas. Ocu-

Craniodiaphyseal Dysplasia
Fig. 1.29. Craniodiaphyseal dysplasia in a 4-year-old girl. There is massive hyperostosis and sclerosis of the skull, facial bones, and mandible. Note prominent maxilla and absent pneumatization of the paranasal sinuses. (From Marden and Wippold 2004)

lar hypertelorism is common. The type and degree of skull involvement are useful diagnostic criteria in the differentiation of craniometaphyseal dysplasia from Pyle disease, in which the skull is affected only mildly or not at all. Craniodiaphyseal dysplasia (OMIM 218300,122860) is characterized by massive hyperos-tosis and sclerosis involving the skull, facial bones, and mandible. The face is severely distorted (leontia-sis ossea), with nasal flattening, ocular hypertelorism, prominence of malar regions, and marked dental malocclusion and abnormal eruption (Gorlin 1994). The paranasal cavities and mastoids do not develop (Fig. 1.29). Cranial and facial passages are obliterated, including optic foramina, internal auditory canals, nasal choanae, and lacrimal ducts (McHugh et al. 1994). Stenosis of the foramen magnum may result in brain stem compression, syringo-hydromyelia, and obstructive hydrocephalus. Thus, compared with craniometaphyseal dysplasia, involvement of the skull is more extensive and severe in craniodiaphyseal dysplasia. In addition, the long bones are uniformly widened and cylindrical rather than club-shaped as they are in craniometaphyseal dysplasia, and exhibit varying degrees of diaphyseal endostosis. All cases are sporadic. In the severe autosomal recessive form of osteopetrosis (Albers-Schon-

berg disease, OMIM 259700) the skull is thickened and dense, without a recognizable diploe. Calvarial thickness may be increased by a factor of 3 or more, resulting in diminution of intracranial volume and, occasionally, tonsillar herniation, cephalocele, and optic nerve sheath dilatation (Cure et al. 2000). Prominent basal sclerosis, with bone deposition along the anterior (but not posterior) occipitomastoid suture, at the basioccipital-exoccipital synchondrosis, and along the spheno-occipital synchondrosis, is noted (Elster et al. 1992). The facial bones are also involved and appear more dense than normal. Impaired vision, nystagmus, optic nerve atrophy, and facial paralysis are common complications, beginning in infancy. Osteomyelitis of the jaw may follow dental extraction (Dyson 1970). Osteopetrosis with late manifestations (juvenile and adult type, OMIM 166600, 259710) may exhibit either sclerosis and thickening of the calvarium (type I) or predominant involvement of the skull base (type II). The sinuses become progressively obliterated (Bollerslev and Mosekilde 1993) (Fig. 1.30). The pattern of skull involvement in the autosomal recessive dysosteosclero-sis (OMIM 224300) includes thickening of the cranial vault and skull base, sclerosis of the orbital roofs, absence of mastoids and paranasal sinuses, and bony encroachment on cranial foramina, resulting in cranial nerve involvement (optic atrophy, abducens and facial palsy, etc.) (Chitayat et al. 1992). Van Buchem disease (hyperostosis corticalis generalisata, OMIM 239100), an autosomal recessive disorder, shows os-teosclerosis of the cranial vault and skull base, mandible, clavicles, and ribs, in association with cortical thickening of the diaphyses of the long and short tubular bones beginning during puberty (van Buchem et al. 1962). Encroachment on cranial nerves, sometimes resulting in optic atrophy and perceptive deafness, may occur as early as the first months of life, well before sclerosis of the skull is perceptible on radiograms (Fryns et al. 1988). Mandibular enlargement and thickening, with an obtuse angle, are striking findings, usually becoming apparent before the second decade. A genome-wide search in a highly inbred Dutch family, in which all patients had a common ancestor about nine generations before, has shown linkage to chromosome 17q11.2 (Balemans et al. 1999). Deletion within this region may cause van Buchem disease, though it does not appear to disrupt the coding region of any known gene (Staehling-Hampton et al. 2002). Hence, the deletion may interfere with the transcriptional regulation of two nearby genes, MEOX1 (the human homolog of the mouse Mox1 gene) and SOST (a gene encoding a novel se

Tricho Dento Osseous Syndrome
Fig. 1.30 a, b. Juvenile osteopetrosis in a 30-year-old man. Ob- The maxilla and mandible are also involved, and the paranasal serve diffuse, homogeneous thickening and sclerosis of the sinuses are partially obliterated cranial vault and skull base. The diploic space is obliterated.

creted protein, sclerostin). Mutations in the SOST gene cause sclerosteosis, but not van Buchem disease (Brunkow et al. 2001). The autosomal dominant form of endosteal hyperostosis, Worth disease (OMIM 144750), is essentially limited to a square jaw with increased gonial angle, asymmetrical enlargement of the facial bones, and torus palatinus (Gorlin and Glass 1977). Sclerosteosis (OMIM 269500) is an autosomal recessive disorder characterized by generalized osteosclerosis and, often, syndactyly and other digital anomalies (phalangeal hypoplasia, radial deviation of the distal phalanges of the 2nd finger, nail dysplasia). The disease is caused by mutations in the SOST gene, which maps to 17q12-q21, the same region as is involved in van Buchem disease. It is particularly common in South African patients of Dutch ancestry, with an estimated frequency of about 1 in 60,000 Afrikaners (Beighton et al. 1976). Changes develop in childhood and are progressive. The face is peculiar, with a prognathic squared mandible, dental malocclusion, prominent forehead, broad and flat nasal bridge, and hypertelorism. Facial nerve palsy, mixed hearing loss, optic atrophy, strabismus, and trigeminal nerve dysfunction are common, especially in adults (Dort et al. 1990). Increased intracranial pressure occurs in about 80% of cases. Roentgeno-graphically, changes resemble those of van Buchem disease, including thickening and sclerosis of the calvaria and skull base, with obliteration of foramina;

osteosclerosis of the mandible, clavicles, ribs, scapulae, vertebral end-plates and pedicles, and pelvis; bone thickening and undertubulation. The mandible is markedly and asymmetrically enlarged, and prog-nathic, with an obtuse angle. Overall, sclerosteosis tends to be more severe than van Buchem disease and is associated with gigantism and digital anomalies (Nager et al. 1983; Beighton et al. 1984; Beighton 1988). In progressive diaphyseal dysplasia (Camu-rati-Engelmann disease, OMIM 131300) there is marked sclerosis of the skull base and the cranial vault. The mandible is sclerotic in about 25% of cases, and occasionally it is significantly enlarged (Demas and Sotereanos 1989). Cranial nerve involvement and endocranial hypertension, sometimes complicated by herniation of cerebellar tonsils through the foramen magnum, are common neurological manifestations (Applegate et al. 1991). Otosclerosis and stapes fixation have been reported (Huygen et al. 1996). Diaphyseal expansion with irregular, cortical thickening involving the mid-dia-physes of the long tubular bones, and narrowing of the medullary cavity are striking features. Tricho-dento-osseous dysplasia (OMIM 190320) is an autosomal dominant disorder characterized by ameloge-nesis imperfecta, taurodontism, and curly hair. The classic form of the disease, type I, exhibits hypoplas-tic yellowish-brown enamel and sclerosis of the long bones, calvaria, and skull base, with sinusal underp-

Paget Calvarium Plain Film

Fig. 1.31 a, b. Paget disease in a 75-year-old woman.Note widespread inhomogeneous osteosclerosis of the cranial vault, with more focal areas of radiodensity producing the 'cotton-wool' appearance. Differentiation between inner and outer tables and diploic space is obscured. The well-defined area of osteol-ysis in the left parietal bone is due to a coincidental arachnoid cyst with resultant focal bone resorption

Fig. 1.31 a, b. Paget disease in a 75-year-old woman.Note widespread inhomogeneous osteosclerosis of the cranial vault, with more focal areas of radiodensity producing the 'cotton-wool' appearance. Differentiation between inner and outer tables and diploic space is obscured. The well-defined area of osteol-ysis in the left parietal bone is due to a coincidental arachnoid cyst with resultant focal bone resorption neumatization. The mandible may be sclerotic, with short ramus, long body, and wide angle (Kula et al. 1996; Lichtenstein et al. 1972). Type II of tricho-den-to-osseous dysplasia shows neither enamel discoloration nor long bone sclerosis. Unlike type I, it involves macrocephaly, with sclerosis and thickening of the skull base and calvaria, and obliteration of the diploic space. Frontal sinuses and mastoids are also obliterated. As Paget disease predominates in the axial skeleton, the skull is a preferential site of involve ment, together with the spine and pelvis (Guyer 1981). Pagetic alterations in the skull vary from foci of osteoporosis circumscripta, which are typical of the active disease stage, to multiple osteosclerotic areas of the inactive stage that obscure the differentiation of outer and inner table from the diploe and give the neurocranium a 'cotton-wool' appearance (Fig. 1.31 a,b). These islands of dense bone may closely mimic osteoblastic metastases. Extensive thickening and sclerosis of the cranial vault, particularly in frontal regions, are occasionally seen. Bony apposition on the outer or inner table is markedly irregular and asymmetrical,with gross alteration of the calvar-ial contour and, occasionally, encroachment on the meninges and brain parenchyma. The facial bones are usually not extensively involved, although sclerotic mandibular lesions (cementomas) may occasionally displace teeth, producing malocclusion. Proliferation of bone in the skull base may cause obliteration of cranial fissures and foramina, with secondary cranial nerve compromise, vascular stretching or occlusion (vertebral and basilar arteries), and internal hydrocephalus. Basilar invagination, i.e., upward displacement of the odontoid into the foramen magnum owing to the effect of gravity and muscle pull, is a typical manifestation of Paget disease, occurring in about one-third of patients, especially females (see section "Basilar Impression" in this chapter). Neurological symptoms result from compression of the medulla and cervical spinal cord. Hyperphosphatasemia (juvenile Paget disease, OMIM 239000), an autosomal recessive disorder that can result from osteoprotegerin deficiency caused by inactivating mutation in the TNFRSF11B (Whyte et al. 2002), is characterized by fever, bone pain, and swelling of the extremities during the 1st year of life, followed in subsequent years by calvarial enlargement, multiple fractures, bowing of long bones, and marked cortical thickening (Bakwin et al. 1964; Dunn et al. 1979). The long bones are greatly expanded with osteoporosis and coarse trabeculation. Headache, hypertension, pseudoxanthoma elasticum, and muscle weakness are common manifestations (Mitsudo 1971). In the long term, changes may be radiographic only. Histological features include metaplastic fibrous bone formation and increased osteoblastic and osteoclastic activity, but no cytoplasmic or nuclear inclusions such as occur in Paget disease (Golob et al. 1996). Radiographic manifestations in the skull, specifically cotton-wool-like lesions of the calvaria, are remarkably similar to those seen in Paget disease. Sclerosis of the skull base, especially in the basi-frontal area, may be striking. The face is usually spared. Root resorption leads to premature loss of teeth (Eyring and Eisenberg 1968). Serum alkaline phosphatase levels may show a 20-fold increase. Serum acid phosphatase and urinary hydroxyproline and leucine aminopeptidase are also elevated.

Mandibular Involvement. Infantile cortical hyperostosis (Caffey disease, OMIM 114000), a generally benign and self-limiting disorder affecting children under 6 months of age, is marked by symmetrical thickening and swelling over the body and ramus of the mandible and/or other bones, including clavicle, tibia, ulna, femur, rib, humerus, maxilla, and fibula. Tender, painful soft tissue swelling occurs in the face, around the orbits, thorax, or extremities, often with a fluctuating course of remission and exacerbation. There is mild fever and irritability. Although cortical bone apposition and enlargement of the mandible is initially symmetrical, residual mandibular asymmetry and malocclusion may supervene. Radiographic evidence of the disease may persist for years after the resolution of clinical symptoms. The disease may occur sporadically, or as a familial disorder following an autosomal dominant inheritance with incomplete penetrance and variable expression (Bull and Feingold 1974). There are some dissimilarities between the two forms. The sporadic form usually has a later onset (10 weeks vs 7 weeks in the familial form), more frequent mandibular, ulnar, and clavicular involvement, and less frequent involvement of the lower limbs (Saul et al. 1982). Conversely, the ribs and scapulae are only rarely affected in the autosomal dominant form (Maclachlan et al. 1984). A severe prenatal form, either sporadic or autosomal recessive, is likely to exist (Labrune et al. 1983).

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  • dawid white
    What does skull bone thickening nean?
    8 years ago
  • Lidya
    What causes thicking of skull bones?
    7 years ago
  • anna
    What causes the plates in an adult skull to overlap and form a ridge?
    6 years ago
  • emmanuel
    Is focal hyoertosis a neurological condition ?
    6 years ago
  • pirkko
    What diseases would cause skull thickening?
    6 years ago
  • megan
    Can late adult onset osteopetrosis cause skull to thicken or develop indentation?
    5 years ago
  • gerardina
    What is significant musical thickening in the maxillary and mastoiditis?
    5 years ago
  • Seija
    Can thickening of the skull bone around occipitand temporal area, jaw area be seen on skull xrays?
    4 years ago
  • vanessa
    What does significant thickening of the calvarium in frontal region indicate?
    4 years ago
    What causes thickening of skull bones?
    4 years ago
  • Janina
    What is sclorsis of the skull?
    4 years ago
  • mikael korpela
    What does focal thickening of inner table of left parietal bone mean?
    3 years ago
    What is thickening of skull vault?
    3 years ago
  • siiri
    What is thickening of venus lake in skull?
    3 years ago
  • pansy
    What is focal calvarial?
    2 years ago
  • biagio
    What causes thickening of forehead bone?
    2 years ago
  • kiros
    Why would scull bone thicken?
    2 years ago
  • Italia
    What causes a thickened area in the frontal skull area?
    1 year ago
  • adiam
    Does CVID cause skull thickening?
    1 year ago
  • medhanit
    What causes thick scaling at the base of your skull?
    11 months ago
    What is sclerosis of skull?
    10 months ago
  • paciano
    What does it mean if the wall of my skull shows thinkening?
    5 months ago
  • salvia
    Is thickening of the calvarium a symptom in pajets disease?
    4 months ago
  • emily
    What is calvarium sclorosis?
    2 months ago
  • consolata
    What causes thick skulls?
    10 days ago

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