Microcystic adnexal carcinoma: review of a potential diagnostic pitfall and management.

Microcystic adnexal carcinoma (MAC) is an uncommon, locally aggressive cutaneous neoplasm that usually presents as a slow-growing, asymptomatic lesion on the head or neck. Microcystic adnexal carcinoma frequently is misdiagnosed due to its histologic appearance on superficial biopsy specimens mimicking other follicular neoplasms. Herein, we highlight a case in which a slow-growing lesion was initially diagnosed as a trichoadenoma following superficial biopsy; however, after surgical excision the pathology revealed a locally aggressive MAC.

Necrobiotic xanthogranuloma without a monoclonal gammopathy.

Necrobiotic xanthogranuloma (NXG) is an indolent non-Langerhans cell histiocytosis characterized by yellow xanthomatous plaques that tend to ulcerate. Necrobiotic xanthogranulomas have a predilection for the bilateral periorbital region and often present with consequential ophthalmic findings. Histopathology usually reveals a distinctive pattern of histiocytic xanthogranuloma with hyaline necrobiosis. Necrobiotic xanthogranuloma has been documented to have a close association with paraproteinemia. We report the case of a 76-year-old man with periorbital NXG without development of a monoclonal gammopathy. Clinically, the patient presented with dry eyes and substantial periorbital edema with multiple yellow indurated plaques. He developed the condition 30 years prior to presentation at which time it was initially diagnosed as xanthelasma. He underwent surgical excision of the lesions 10 years prior to the current presentation and biopsy results revealed a diagnosis of NXG. The periorbital lesions recurred several years prior to presentation, prompting annual computed tomography scans to rule out ocular invasion. Periorbital edema and plaques improved during a 6-month regimen of acitretin but returned to baseline just months after discontinuation.