Syringocystadenocarcinoma Papilliferum-An Uncommon Malignant Adnexal Neoplasm at an Unusual Location.

Syringocystadenocarcinoma Papilliferum (SCACP) is a rare adnexal malignant neoplasm. Most of the cases present with a long standing mass with a sudden progression in size. A 60-year-old female presented with history of swelling over the anterolateral aspect of left thigh since three years. The lesion was associated with history of pain and ulceration. Grossly, the external surface showed three ulcerated areas. The largest ulcer measured 4×5.5 cm. On cut section, the tumour showed variegated appearance consisting of grey-white to pink areas, multiple cysts, focal necrosis and hemorrhagic areas. Microscopically, tumour cells were arranged in papillary configuration, solid sheets, tubular and acinar pattern. Individual tumour cells showed pleomorphic vesicular nucleus and mitotic figures. The intervening connective tissue showed dense chronic inflammatory cell infiltrate composed of lymphocytes, plasma cells and eosinophils. Also seen were areas of necrosis and Gamna-Gandy body. Based on histological features, a diagnosis of malignant appendageal tumour of the skin with apocrine differentiation, favouring SCACP was offered. By Immunohistochemistry (IHC), tumour cells showed focal positivity for CEA and negative for GCDFP-15. IHC may be helpful, but a pathologist has to primarily depend on the histopathological characteristics of the lesion for diagnosing the condition. [ABSTRACT FROM AUTHOR]