Giant cell tumor of distal phalanx in an adolescent with Goltz-Gorlin syndrome.

Summary: Giant cell tumor of distal phalanx in an adolescent with Goltz-Gorlin syndrome: We report on a unique case of a young female patient with the Goltz-Gorlin syndrome who developed a giant cell tumor of bone in the distal phalanx of the thumb. This case is noteworthy because of the combination of some unusual features. Firstly, it is only the fifth case report on the association of giant cell tumor of bone and the Goltz-Gorlin syndrome. Also the localization of the lesion in the bones of the hand and the presentation at adolescent age is rarely seen.Key-words: Giant cell tumor of bone Goltz-Gorlin syndrome - Thumb - Adolescent.INTRODUCTIONThe Goltz-Gorlin syndrome or focal dermal hypoplasia is a rare congenital disorder. This clinical entity was first described in 1962 by Goltz et al. (7). Cutaneous features include dermal atrophy and linear pigmentation, fat herniation through defects in the skin and multiple papillomas of mucous membranes. Musculoskeletal features consist of microcephaly and digital anomalies like polydactyly, syndactyly, camptodactyly and absence of rays. Osteopathia striata is a frequent radiographic finding. This is characterized by fine linear striations in long bones and the pelvis seen on radiographs. Ocular anomalies include microphtalmia, iris and choroid coloboma and strabismus.Genetic studies have identified a heterozygous mutation in the PORCN gene, located on chromosome Xp 11.23. [OMIM # 305600], The PORCN gene codes for a protein called Porcupine, an O-acyltransferase located in the endoplasmatic reticulum that is required for Wingless protein (Wnt) modification and excretion. Wnt plays an important role in epithelial development and differentiation (18). Inheritance of Goltz-Gorlin syndrome is X-linked dominant with a high in utero mortality in males. Therefore the syndrome is found most commonly in females, with scarce case reports on males.Giant cell tumors (GCT) can arise from tendon sheats and bones. Giant cell tumor of bone is a benign mesenchymal tumor that accounts for 6% of all bone tumors. Typically these tumors present in the epiphyseal and metaphyseal regions of long bones. The second most frequent site is the axial skeleton, mainly the sacral bone. Literature reports metastasis to the lungs in 2% of cases (14).Histologically GCT of bone consists of spindle-like stromal cells and osteoclast-like multinucleated giant cells. Cytologically the mononuclear stromal cells are the neoplastic components of the tumor. These cells direct the pathogenesis of the tumor through promotion of giant cell formation. Because of their osteoclast-like properties, especially bone resorption, the giant cells are responsible for the locally destructive effect of the tumor (5).Radiographically GCT of the bone manifests as an expansile osteolytic lesion. Campanacci et al. introduced a three grade classification system, based on radiographic assessment of tumor borders and presence of cortical destruction or soft-tissue mass (4).Radiographic differential diagnosis consists of other lytic bone lesions including aneurysmal bone cysts, giant-cell reparative granuloma, enchondroma, osteoid osteoma, epidermoid cyst, brown tumor of hyperparathyroidism, chondromyxoid fibroma, chondroblastoma and metastatic tumor. Enchondroma is by far the most common in the differential diagnosis of an expansile lytic lesion in the small bones of the hand.We report a case of a 13-year-old patient with a giant cell tumor in the distal phalanx of the thumb. Three features make this case noteworthy: the rare association of GCT with the Goltz-Gorlin syndrome, the rare location of a GCT in the distal phalanx of the thumb and the presentation of GCT at the age of 13.CASE DESCRIPTIONA 13-year-old, right handed girl presented at our hand clinic with a painful swelling of the right thumb.Her medical history revealed diagnosis of the Goltz-Gorlin syndrome four days after birth. …