Trichoadenoma of Nikolowski.

Trichoadenoma of Nikolowski is a rare benign cutaneous tumor, which is usually solitary, nodular and occurs on the face or buttocks any time during adult life. The morphological differentiation of trichoadenoma is situated between a trichofolliculoma and a trichoepithelioma with hair follicle-like direction of differentiation. We report this case of trichoadenoma in a 28-year-old man who presented with a solitary nodular and ulcerated swelling in the gluteal region, gradually increasing in size. Excision biopsy revealed characteristic features consistent with trichoadenoma. We report this case in view of its rarity.

Osteochondroma-like parosteal osteosarcoma.

Parosteal osteosarcoma is a well-differentiated, predominantly fibro-osseous variant of osteosarcoma, accounting for 5% of all osteosarcomas. We report a case of parosteal osteosarcoma in the metaphyseal area of right femur, of 2 years' duration in a male aged 35 years. It was mistaken for osteochondroma in the initial biopsy, and the possibility of bizarre parosteal osteochondromatous proliferation (BPOP) was also considered. Subsequent excision of the tumor showed it to be a parosteal osteosarcoma. The patient had recurrence of the lesion after 1 year, and he attended a cancer institute. Follow-up showed metastases of the tumor on bone scan.