Hardcastle Syndrome

At a glance

A rare genetic disorder characterized by skeletal dysplasia, diaphyseal sclerosis, medullary stenosis, pathological bone fractures, and infarction, leading to malignant histiocytoma transformations.

Synonyms

Diaphyseal Medullary Stenosis with Malignant Fibrous Histiocytoma; Bone Dysplasia with Medullary Fibrosarcoma; Hereditary Bone Dysplasia with Malignant Fibrous Histiocytoma.

Incidence

Unknown but rare. Only four families affected with this medical condition have been reported in the literature since its first recognition by Arnold in 1973.

Genetic inheritance

Autosomal dominant pattern of inheritance with probable variable penetration of the gene. Gene linkage studies have isolated the syndrome to 9p22-p21.

Pathophysiology

Precise pathophysiology is unknown, but the region of chromosome 9 has been linked to the syndrome. It contains a number of genes whose protein products are involved in growth regulation, protein synthesis, and breakdown. At a cellular level, abnormal fibroblast function is the most likely cause of dysplasia.

Diagnosis

Made by clinical features and characteristic radiologic findings, which include diffuse diaphyseal medullary stenosis with overlying endosteal cortical bone thickening, scalloping, metaphyseal striations, infarctions, scattered sclerotic bone areas, and decrease of metaphyseal bone density with sparing of the epiphysis. Family members at risk are advised to have yearly radiographs of the lower limbs after puberty, and those with abnormalities on plain radiographs should have yearly bone scintigraphy scans thereafter (scintigraphy scanning will detect tumors within areas of dysplasia). Biochemical and parathyroid screening are normal.

Clinical aspects

Characterized by bone dysplasia with cortical growth abnormalities, which symmetrically affect the long tubular bones of the extremities. Spine and pelvis are unaffected. Radiographic evidence of the bone dysplasia has been reported from puberty onward, with a peak between the second and fifth decade of life. Of affected individuals, 35% develop malignant fibrous histiocytoma, a highly malignant bone sarcoma. Survival following diagnosis of malignant fibrous histiocytoma is very poor (usually <2 years). Morbidity results from pathologic fractures (prolonged healing and nonunion occur), bowing of the limbs, wasting of affected limbs, and painful debilitation. An association with presenile cataracts has been reported. Death is most often caused by multiple metastases (brain, lung, liver, kidney, heart, and bone). Current treatment is directed toward early diagnosis of malignant changes in dysplastic areas followed by amputation with or without chemotherapy.

Precautions before anesthesia

Detailed clinical history and examination to determine the extent of bone dysplasia and evidence of malignant changes and tumor metastases. If indicated (metastatic disease), assess cardiac function (ECG, echocardiography), pulmonary function (chest radiograph, spirometry, arterial blood gases), liver function, and renal function (blood urea nitrogen, electrolytes). CT or MRI scans (brain, lungs, heart, liver, kidney, bones) and hematologic screening (complete blood count and clotting screen) may be ...