Pilomatrix Carcinoma At The Popliteal Fossa: A Case Report With A Review Of The Literature

摘要

Pilomatrix carcinoma is a rare, low-grade malignant tumour of hair matrix. In this report, we present a case of Pilomatrix carcinoma in a 52 year male patient ,which occurred on a popliteal fossa, which is a very rare site. Histological findings have been discussed. Introduction Pilomatrix carcinoma is a malignant counterpart of pilomatrixoma. It is so rare a disease that only 80 cases have been reported (1). Gromiko observed pilomatrix carcinoma invading adjacent tissues and recurring for the first time in 1927. (2) Lopansri and Mihm reported a case of pilomatrixoma with malignant features and proposed the term “pilomatrix carcinoma” or “calcifying epitheliocarcinoma of Malherbe.” (3) This neoplasm can exhibit local aggressive behaviour and occasionally distant metastasis. Most pilomatrix carcinomas occur on the head and neck. (4) Few cases have been reported at other sites like axilla and spine. (5,6) To the best our knowledge, this rare tumour has not been reported in popliteal fossa. Case Report A 52 year-old male patient came to General Surgery Out Patient Department with a slowly growing fungating growth over the popliteal fossa. The patient had this growth for a period of 2 years. Clinical diagnosis was Squamous cell carcinoma. Wide local excision was done and sent for histopathological examination. The specimen received showed a fungating, proliferative ulcerated mass with surrounding skin. The mass measured 12x11x10 cm. External surface of the mass was necrotic, friable and showed sand grain appearance. (fig 1) Cut section was grayish white with cystic change and areas of necrosis (fig 2) Haematoxylin and Eosin sections studied showed a tumor covered by ulcerated epidermis. The tumor showed nests of basophilic cells with deeply basophilic nuclei and scanty cytoplasm and indistinct cell margins. The nests of tumor cells showed eosinophilic areas of abrupt keratinisation (fig 3) These cells were seen surrounding eosinophilic shadow or ghost cells which show loss of nuclei. (fig 4) The basaloid cells showed pleomorphism, darkly stained nuclei, anisonucleosis and mitotic figures. (fig 5 and 6) Focal areas of necrosis were also seen. (fig 7) Margins of tumour mass were seen infiltrating surrounding stroma. (fig 8) The tumor cells showed areas of perineural invasion. (fig 9) The stroma of the tumor showed foreign body giant cells and lymphocytic reaction. Based on these findings, histopathological diagnosis of pilomatrix carcinoma was given.