Abstract

A 75-year-old male patient presented with multiple poorly-to well-demarcated erythematous indurated non-scaly plaques over the back and bilateral lower extremities. The initial biopsy was suggestive of cutaneous T cell lymphoma, CD30 negative; however, within two months, the lesions became confluent with a dark red to brown margins, necrosis, ulceration, and bullae formation. Systemic signs/symptoms of fever and weight loss also developed. The disease progressed to involve the chest and upper extremities, while computed tomography was negative for visceral involvement. Repeat biopsy revealed diffuse involvement of the epidermis and dermis by an atypical lymphoid infiltrate composed of medium to large lymphocytes with irregular nuclear contours, moderate amounts of eosinophilic cytoplasm, variably condensed chromatin, and scattered mitotic figures. Significant epidermotropism and marked papillary dermal edema were present. The lymphoid infiltrate was predominately oriented around the vessels and adnexa, with extension into the interstitial spaces. Immunohistochemical studies revealed positive staining for CD3, BCL-2, CD43, TIA-1, and perforin. The neoplastic lymphocytes were negative for CD20, CD2, CD5, CD7, CD4, CD8, CD30, BCL-6, Tdt, CD34, granzyme, and βF1.  The proliferative index by Ki-67 was markedly increased. The histomorphologic and immunohistochemical findings prompted further evaluation, which revealed positive staining for TCR-delta within the neoplastic T lymphocyte population.Given these findings, a diagnosis of primary cutaneous gamma delta T cell lymphoma (PCGDTCL) was established. We present this case to highlight the rapid clinical progression, spectrum of histomorphologic and immunohistochemical findings, and the diagnostic challenges associated with a rare, aggressive entity.