Adamantinoma of the Right Tibia Case Study

Adamantinoma of the Right Tibia Case Study INTRODUCTION: Adamantinoma is low grade malignant tumor of fibroblast origin. Also called as primary epidermoid carcinoma of bone, malignant angioblastoma or epithelial tumor of bone. It was first described by Fischer in 1913. 1 It represents less than 0.4% of all malignant bone tumors. 2 The exact origin of adamantinoma is unknown, the classic variant is composed of epithelial cells and osteofibrous components. It is more prevalent in men than in women, ratio being 5:4. The common age of presentation is in the second decade, though it can vary greatly between the second to fifth decades. 3 The common site of occurrence is the ramus of the mandible. The other uncommon locations include shaft of long bones (97%), mid-shaft of tibia (80%-85%). 4 Other rare locations includes the humerus, ulna, femur, fibula and radius but ribs, spine, metatarsal and carpal bones. 5 The characteristic features of adamantinoma is slow, gradual development with high chances of local recurrences and also metastases to lungs. 6 In this case study, we have presented a rare histological acanthomatous variant of adamantinoma of the right tibia with metastases to the right inguinal region. CASE REPORT: A 45 year old male patient presented with history of pain in right leg since 3-4 months, insidious onset, gradually progressive, aggravated on exercise, relieved on rest and medication. Later patient had no relief on medication. There was no history of trauma or fall preceeding to onset of symptoms. The patient also complained of swelling in the right groin since 1 month, without pain. On examination, the patient was stable. Local examination showed, a swelling of about 5X3cm in the upper end right leg, tender, well defined, hard in consistency, smooth surface, involving the right knee joint line. There was restriction of movement, but range of movements was present. Examination of right inguinal region revealed a 7X6cm firm, non-matted mass, immobile, non-tender, non-reducible, non -pulsatile mass. Local examination of penis, scrotum, anal canal, hernia orifices was normal. Baseline investigations were done, all the haematological parameters were normal, ultrasound abdomen and chest radiograph was normal. Plain radiograph of right tibia showed large central lytic lesion with sclerotic margins, involving the upper end and shaft of tibia without involvement of right knee joint. Supra-patellar amputation of right leg with right inguinal and right external iliac nodal dissection was done. Histopathological examination of the mass was done. The reported was suggestive of acanthomatous adamantionoma. The features are as described, central area of squamous cell nests which were well differentiated with keratinization surrounded by a rim of myxoid cells. Further immunohistochemistry(IHC) study was done to confirm the diagnosis. IHC was also consistent with the diagnosis and confirmed the diagnosis. Positivity was found for cytokeratin(CK), EMA, CK-19, CK-5, CK-6, P-63 , and Ki-67 and vimentin. Also metastases to right inguinal lymph node was confirmed. DISCUSSION: The first bone tumor with epithelial characteristic was reported by Maier in 1900, later in 1913 Fischer termed it as adamantinoma. It is more common in men than in women. The age of presentation varies between the second to fifth decade. The uncommon sites includes the shaft of long bones(97%), of which the mid-shaft of tibia being the most common site(80-85%). The symptoms at presentation include pain with localised swelling. Swelling is the most common symptom. Pain may be present due to history of repetitive trauma associated with adamantinoma. 7 Adamantinoma is low grade malignant tumor, and can metastasize to loco-regional nodal areas and to lungs at presentation. The patient in the case report was also a middle aged man in the fifth decade with pain and swelling in the right tibia since 3-4 months and swelling in the right groin.