Cortical Thickening

► [Increase in thickness and density of the cortex, hyperostosis]

This section deals with a heterogeneous group of unrelated disorders, either congenital or acquired, focal or widespread, whose pathological and radiographic stigmata are those of cortical hyperostosis. Conditions involving generalized bone sclerosis, such as osteopetrosis, dysosteosclerosis, pyknodysostosis and osteosclerosis, are addressed in Chapter 9. Thickening of bone cortex may be secondary to overproduction or diminished resorption of cortical bone. Overproduction may be related to periosteal bone formation, endosteal bone formation, or both. The term periostitis defines the pathologic situation characterized by infiltration of the periosteum by inflammatory cells, elevation and/or violation of the periosteal membrane, and new bone deposition in the periosteum or the soft tissues adjacent to it (Spjut and Dorfman 1981). Subsequent merging of the newly formed periosteal bone with the cortex leads to cortical hyperostosis. Compared with that in adults, the periosteal membrane in infants and children is thicker, more highly vascularized, metabolically more active, and more loosely attached to the underlying cortex. This may well explain two characteristics of the periosteal membrane of the immature skeleton: the increased susceptibility (a) to being lifted from the parent bone and (b) to being stimulated to form osseous tissue. The following discussion will focus first on situations of cortical hyperostosis associated with periostitis and next on situations of 'primary' cortical hyperostosis without periostitis.

The list of diseases associated with periostitis is very long indeed and includes infections (osteomyelitis, syphilis, tuberculosis), tumors (leukemia, lymphoma, metastases, primary bone tumors, eosinophilic granuloma), metabolic disorders (copper deficiency, hyperphosphatasia, hyperparathy-roidism, hyperthyroidism, rickets, scurvy, hypervita-minosis A), skin disorders (ichthyosis congenita, urticaria pigmentosa, pyoderma, burns, frostbite, chronic cellulitis), trauma, juvenile rheumatoid arthritis, sickle cell anemia, prostaglandin-induced periostitis (Fig. 5.17),dactylitis, venous insufficiency, and several bone disorders (pachydermoperiostosis, secondary hypertrophic osteoarthropathy, idiopathic cortical hyperostosis, fibrous dysplasia, Paget disease, recurrent symmetrical periostitis) (Reeder and Felson 1993; Kozlowski and Beighton 1995). However, diffuse periosteal new bone deposition can be

Images Hyperphosphatasia

Fig. 5.17. Prostaglandin-induced periostitis in a 45-day-old child. This baby with severe tetralogy of Fallot was given prostaglandin Ej, a specific relaxant of ductal smooth muscle, intravenously to maintain the patency of the ductus arteriosus and allow adequate pulmonary blood flow before the necessary surgical intervention. Periostitis developed in the first few days after treatment. Note periosteal thickening along the external diaphyseal surface of both femurs

Fig. 5.17. Prostaglandin-induced periostitis in a 45-day-old child. This baby with severe tetralogy of Fallot was given prostaglandin Ej, a specific relaxant of ductal smooth muscle, intravenously to maintain the patency of the ductus arteriosus and allow adequate pulmonary blood flow before the necessary surgical intervention. Periostitis developed in the first few days after treatment. Note periosteal thickening along the external diaphyseal surface of both femurs seen in normal infants, especially prematures, perhaps in response to exuberant bone growth. The periosteal reaction accompanying osteomyelitis is often multi-layered like 'onion peeling,' a pattern similar to that encountered in certain malignant neoplasms (Fig. 5.18 a,b), including Ewing's sarcoma (OMIM 133450). When the periosteal reaction associated with osteomyelitis involves only a single layer of thick bone, the changes are reminiscent of eosino-philic granuloma or traumatic periostitis (Resnick and Niwayama 1995b). A thick periosteal reaction is seen in the presence of eosinophilic granuloma once the lesion originally located within the medullary cavity encroaches on the cortex and erodes its en-dosteal surface. In childhood leukemia and lymphoma, periosteal bone formation is secondary to invasion of the cortex via the haversian canals by the proliferating marrow cells. These cells then reach a subperiosteal location, causing elevation of the pe-riosteal membrane and bone formation. The pe-riosteal new bone deposition of the healing phase of a fracture results in single or multiple bony shells, which subsequently merge with the parent bone. In the battered child syndrome, multiple fractures with periosteal reactions at different stages of evolution are a clue to the diagnosis. A special case of periosteal new bone deposition is that occurring in the lower extremities in patients with chronic venous insufficiency, possibly as a response to local hypoxia (Dannels and Nashel 1983). The term dactylitis refers to a pathologic process of varying etiology (sickle

Fig.5.18a,b. Primitive neuroectodermal tumor (PNET) in a 13-year-old boy.a Anteroposterior and b lateral radiograph of the shank shows cortical thickening and pe-riosteal irregularities and spiculation along the lateral and posterior aspects of the tibia. The epiphysis is not involved. The boy had tuberous sclerosis. (From Hindman et al. 1997)

Tuberous Sclerosis Radiography

Fig.5.18a,b. Primitive neuroectodermal tumor (PNET) in a 13-year-old boy.a Anteroposterior and b lateral radiograph of the shank shows cortical thickening and pe-riosteal irregularities and spiculation along the lateral and posterior aspects of the tibia. The epiphysis is not involved. The boy had tuberous sclerosis. (From Hindman et al. 1997)

cell anemia,tuberculosis,syphilis,leprosy,fungal and pyogenic disorders, leukemia, scurvy, hypervita-minosis A, trauma, infantile cortical hyperostosis) involving a periostitic reaction of the short tubular bones in the hands and feet, with or without bone destruction. Soft tissue swelling is uniformly present (Worrall and Butera 1976; Andronikou and Smith 2002). In primary hypertrophic osteoarthropathy (pachydermoperiostosis, OMIM 167100), an autosomal dominant condition with enlargement of the hands and feet, digital clubbing, coarsening of the skin of the face and scalp, and swollen joints, a cardinal feature is widespread and symmetrical cortical thickening, which is most prominent in the tubular bones of the extremities (Vogl and Goldfischer 1962). Periostitis extends across the epiphyses and produces a shaggy appearance of the bony contour, resulting in expansion of the diaphyses and narrowing of the medullary cavity. The familial incidence of the disease has long been recognized (Rimoin 1965). Recessive inheritance is suggested by the several examples of consanguineous parents (Matucci-Cerinic et al. 1989). Changes in the peripheral blood supply, resulting in local hypoxia, have been suggested as the initiating event of periosteal new bone formation (Fam et al. 1983). Additional findings include liga-mentous ossification, bony bridges across joints causing joint ankylosis,soft tissue swelling of the distal digits, and tuftal osteolysis (Joseph and Chacko 1985). The findings in pachydermoperiostosis resemble those of secondary hypertrophic osteoarthropa-thy, an association of digital clubbing, arthritis, and periostitis that can arise as a complication of various diseases, including bronchogenic carcinoma, pleural mesothelioma, pulmonary abscess, bronchiectases, Hodgkin lymphoma, cyanotic congenital heart diseases, biliary cirrhosis, ulcerative colitis, Crohn disease, and others (Sillero Garcia et al. 1978). Lack of family history,late onset,significant pain and tenderness about the joints, and linear periosteal bone formation not usually extending into the epiphysis are distinctive features of the condition (Fig. 5.19 a-c). Of the several theories proposed to explain the pathogenesis of the condition, none of which is entirely adequate (Resnick and Niwayama 1995a),those that have gained the most support include increased vascular flow carrying poorly oxygenated blood to the periosteum (Racoceanu et al. 1971), presence of humoral substances toxic to the periosteum (Jao et al. 1969), and a neurogenic mechanism mediated by the vagus nerve (Rutherford et al. 1969). In thyroid acropachy, an uncommon complication of thyrotoxi-cosis usually arising several years after the onset of treated hyperthyroidism, clinical and radiographic

Fig. 5.19a-c. Hypertrophic osteoarthropathy, secondary, in a 13-year-old boy with na-sopharyngeal carcinoma. Note linear periosteal new bone formation (arrows) involving the diaphyses of the long bones in the upper (a) and lower (b, c) extremities. (From Varan A et al. 2000)

Fig. 5.19a-c. Hypertrophic osteoarthropathy, secondary, in a 13-year-old boy with na-sopharyngeal carcinoma. Note linear periosteal new bone formation (arrows) involving the diaphyses of the long bones in the upper (a) and lower (b, c) extremities. (From Varan A et al. 2000)

Juvenile Hypertrophic Osteoarthropathy

Fig. 5.20 a, b. Infantile cortical hyperostosis (Caffey disease) in a 2-month-old male baby (same case as in Fig. 2.23). a Note marginal hy-perostosis on the lateral edge of the left ilium, extending from the iliac crest to the mid-portion of the acetabular cavity. b Observe massive cortical new bone formation encasing the shaft of the tibia and fibula. The femur and epiphyses are not involved

Fig. 5.20 a, b. Infantile cortical hyperostosis (Caffey disease) in a 2-month-old male baby (same case as in Fig. 2.23). a Note marginal hy-perostosis on the lateral edge of the left ilium, extending from the iliac crest to the mid-portion of the acetabular cavity. b Observe massive cortical new bone formation encasing the shaft of the tibia and fibula. The femur and epiphyses are not involved

Pretibial Myxedema

manifestations include exophthalmos, soft tissue swelling of the fingers and toes, pretibial myxedema, clubbing of the fingers, and periostitis (Resnick 1995). Periosteal proliferation, primarily involving the diaphyses of the metacarpals, metatarsals, and proximal and middle phalanges, especially at their radial ends, is characteristic (Vanhoenacker et al. 2001). Extension to other bones, including the long bones, is uncommon. Periosteal new bone formation follows soft tissue infiltration with myxedematous tissue, but the ultimate cause of this process remains unknown. Pretibial myxedema and a clinical history of thyroid dysfunction are distinguishing features. Infantile cortical hyperostosis (Caffey disease, OMIM 114000) is a rare disorder with onset before the 5th month of life, presenting as fever of abrupt onset and soft tissue swelling. The radiographic stigmata of the disease are those of a periosteal bone reaction (Jackson and Lyne 1979). The mandible, clavicles, and ribs are the bones most frequently involved, but changes at other sites, notably the tubular bones, are also common (Finsterbush and Rang 1975) (Fig. 5.20a,b). Cortical hyperostosis, the hallmark of the disease, results from blending of the newly formed bone in the soft tissues adjacent to the periosteum with the cortex of the parent bone. In the long bones, the lesions of Caffey disease are confined to the shafts, whereas the epiphyses are often spared. Distribution of the lesions is asymmetrical. In many instances, clinical and radiographic manifestations improve and subside over a period of 6 months to 1 year. In a few cases, the disease course is less favorable, with recurrences well into adult life (Pajewski and Vure 1967; Taj-Eldin and Al-Jawad 1971). The pathogenesis is unknown. The inflammatory nature of the acute disease manifestations has led to the hypothesis of an immune reaction triggered by a viral infection (Silverman 1976) or an allergic response to altered collagen tissue (McEnery and Nash 1973). A vascular occlusion secondary to thrombocytosis has also been suggested (Pickering and Cuddigan 1969). Although the disease has somewhat unusual features for a hereditary disorder (it rarely appears after 5 months of age; it is characterized by fever and swelling of involved bones; skeletal abnormalities disappear over time), its occurrence in many members of the same family over one or more generations has underscored the importance of genetic factors, autosomal dominant inheritance being the most likely (Gerrard et al. 1961; van Buskirk et al. 1961).

A number of metabolic disorders and intoxications are characterized by cortical hyperostosis in the tubular bones. In rickets and scurvy in children the radiographic pattern is sometimes similar to that of Caffey disease, although absence of epiphyseal involvement and spontaneous resolution are distinctive features of the latter. Cortical hyperostosis accompanying hypervitaminosis A is obvious at around 1 year of life, affecting the metatarsals and sparing the mandible and facial bones (Frame et al. 1974; Lian and Wu 1986). It can be impossible to differentiate prostaglandin-inducedperiostitis from Caffey disease. Fluorosis is characterized by osteoporosis in the early stages, and by a later appearance of exuberant and irregular periosteal bone deposition, osteophy-tosis, and ligamentous ossification (Lian and Wu 1986). GM1 gangliosidosis type I (OMIM 230500), a storage disease with accumulation of ganglioside in neurons, in histiocytes of the liver and spleen, and in renal glomerular epithelium, involves severe cerebral degeneration leading to death within the first 2 years of life and skeletal deformities resembling those seen in Hurler disease. Radiographically the condition is also undistinguishable from mucolipidosis II (I-cell disease, OMIM 252500), and it is characterized in early infancy by abundant periosteal bone formation of the long tubular bones, uniformly wide tubular bones in the hands and feet, rib widening, coarse tra-becular pattern, and mild vertebral abnormalities. In later infancy and early childhood, dysplasia of the pelvis, overconstriction and irregular contour of the shafts of the long tubular bones, and osteoporosis become apparent (Spranger et al. 1974).

Distinct skeletal dysplasias feature variable degrees of cortical thickening. A combination of exuberant periosteal and endosteal bone formation in the diaphyses of the long bones, symmetrical in distribution and with a fusiform appearance of the cortex and smooth outer contour, is typical for diaphy-seal dysplasia (Camurati-Engelmann disease, OMIM 131300) (Kaftori et al. 1987; Kumar et al. 1981). The process of bone resorption and formation is intensely active in this disorder. A similar but much milder and more localized radiographic pattern occurs in hereditary multiple diaphyseal sclerosis (Ribbing's disease, OMIM 601477) (Seeger et al. 1996). Cortical thickening can also result from new bone apposition at the endosteal side of a tubular bone. The van Buchem type (OMIM 239100) and the Worth type (OMIM 144750) of endosteal hyperostosis are characterized by widespread osteosclerosis, with predominant involvement of the skull and mandible. Symptoms are more severe in van Buchem disease than in Worth disease. The autosomal recessive van Buchem disease occurs early in life and takes the form of severe mandibular enlargement, compromise of cra-

Van Buchem Disease

Fig. 5.21. Melorheostosis in a 20-year-old woman. Irregular, thickened bars of tibial sclerosis extend longitudinally from the cortical profile deep into the medullary cavity. (From Brown et al. 2000)

nial nerves, widened nasal bridge, prominent forehead, and cortical thickening of the tubular bones with periosteal excrescences (Eastman and Bixler 1977). The autosomal dominant Worth disease is clinically benign, manifesting in late childhood with asymmetrical enlargement of the facial bones, especially the jaw, and palatal thickening (torus palati-nus). The cranial nerves are not usually involved. The tubular bones show endosteal hyperostosis, with encroachment of variable extent on the medullary cavity, in the absence of any obvious evidence of severe modeling defects (Greenspan 1991). Sclerosteo-sis (OMIM 269500) is clinically and radiographically similar, and probably related, to endosteal hyperosto-

sis. This recessive sclerosing disorder is characterized by gigantism, a characteristic facies with prominent asymmetrical mandible, a broad and flat nasal bridge, hypertelorism, cranial nerve palsies, deafness, variable syndactyly of the 2nd and 3rd fingers with radial deviation, nail dysplasia, and possibly increased intracranial pressure in adulthood. The tubular bones show cortical sclerosis and thickening, and lack of diaphyseal constriction. The process of osteosclerosis is widespread, with predominant involvement of the skull and mandible, and significant involvement of the spine and pelvis (Beighton 1988). The main radiographic feature in melorheostosis (OMIM 155950) is the presence of dense osseous excrescences abutting on the cortical profile of one bone, or of different bones within the same limb, and extending along the longitudinal bone axis in the shape of flowing candle wax (Freyschmidt 2001) (Fig. 5.21). Hyperostosis is mainly cortical, but endosteal hyperostosis with secondary medullary stenosis also occurs. The pathogenesis is obscure. Based on the specific pattern of lesion distribution, the role of sclerotomes, corresponding to areas of the embryonic skeleton supplied by individual spinal sensory nerves, has been emphasized by Murray and McCredie (1979), who speculate that the sclerosing lesions represent the late result of a segmental sensory nerve lesion. Melorheostosis has been reported in association with other sclerosing dystrophies, including osteopoikilosis and osteopathia striata (Abrahamson 1968). Other possible associations include neurofibromatosis type 1, tuberous sclerosis, infantile cortical hyperostosis, Gardner syndrome, and fibrous dysplasia. In hereditary hyperphosphata-sia (juvenile Paget disease, OMIM 239000) there is generalized demineralization, calvarial thickening, expansion and bowing of the long tubular bones, and widening of the short tubular bones. Alkaline phos-phatase is elevated. Thickening of the cortices on the inner side of the bowed long bones and loss of the discrete cortical shadow in other sites are features specific to this condition (Fig. 5.22a,b). The bone manifestations are bilateral and symmetrical, and there is an increased tendency to fractures (Guibaud 1970). Neurofibromatosis type 1 (OMIM 162220) can show massive and bizarre periosteal bone overgrowth. Moreover, bending deformities of the tibias, with an-terolateral angulation, and gracile, malformed fibulas, are characteristic. The pathogenesis of periosteal thickening is not known. Subperiosteal hemorrhages and/or soft tissue infiltration by neurofibromas that are subsequently incorporated into the cortex are probably primary events, but an intrinsic abnormali

Ichthyosis Deafness

Fig. 5.22 a, b. Hereditary hyperphosphatasia in a 15-month-old trabeculation and loss of corticomedullary differentiation. The girl. The long bones in the upper (a) and lower (b) extremities femora are bowed, and there is prominent cortical thickening are markedly widened, and are undermineralized, with coarse on the inner side of the bowing. (From Tuysuz et al. 1999)

Fig. 5.22 a, b. Hereditary hyperphosphatasia in a 15-month-old trabeculation and loss of corticomedullary differentiation. The girl. The long bones in the upper (a) and lower (b) extremities femora are bowed, and there is prominent cortical thickening are markedly widened, and are undermineralized, with coarse on the inner side of the bowing. (From Tuysuz et al. 1999)

ty of the periosteum cannot be ruled out (Steen-brugge et al. 2001; Pitt et al. 1972).

Osteomas are single lesions arising from the periosteum and each consisting of a protruding mass of abnormally dense but otherwise normal bone. They occur most commonly in the skull and facial bones, but can also be found in the tubular bones (Stern et al. 1985; Broderick et al. 1980). The pathogenesis is uncertain, one theory suggesting that osteomas are the sclerotized end-stage of fibrous dysplasia (Jaffe 1958) while another disputes that they represent hamartoma-like processes (Aegerter and Kirkpatrick 1975). Osteomas are easily distinguished from osteo-chondromas on the basis of the absence of spongy bone and cartilaginous cap. Multiple osteomas can be the first manifestation of Gardner syndrome (OMIM 175100), an autosomal dominant disease characterized by colonic polyposis, osteomatosis, and soft tissue tumors (Chang et al. 1968). In the tubular bones, including those of the hands and feet, the osseous lesions do not have the usual appearance, but rather manifest as localized cortical thickening that simulates the nodular osseous excrescences of tuberous sclerosis.

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  • Leon
    What is cortical and periosteal thickening?
    5 years ago
  • Consuelo
    What is cortical thickening of the tibial cortex?
    3 years ago
  • ponto
    Can scleroderma cause periosteal thickening of the metatarsals?
    3 years ago
  • Andrea
    What does smooth cortical thickening at the base of finger?
    3 years ago
  • Maximilian MacDonald
    What does cortical thickening around the fibula mean?
    3 years ago
  • Uta
    Is there cortical thickening in fibrous dysplasia?
    5 months ago
  • teighan mitchell
    What is cortical thickening of the femur?
    2 months ago
  • rachel stiver
    What does osseous cortical thickening of the tibia mean?
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