Cutaneous involvement by angioimmunoblastic T-cell lymphoma: a unique histologic presentation, mimicking an infectious etiology

Angioimmunoblastic T-cell lymphoma (AILT) is an aggressive peripheral T-cell lymphoma that is frequently accompanied by a cutaneous eruption. The cutaneous findings most commonly consist of a maculopapular eruption on the trunk. However, purpura, infiltrated or urticarial plaques, papulovesicular lesions, nodules, and erythroderma have also been reported. Histologic findings in the lymph node are characteristic, while those in the skin may show one of four patterns. Here, we review the previously reported histologic patterns and present a case of AILT involving the skin with a unique histologic appearance of necrotizing granulomas with abundant histiocytes and eosinophils, mimicking an infectious etiology.

Cutaneous Plasmacytosis

Cutaneous plasmacytosis is a rare disorder that typically affects middle-aged to older individuals of Asian, particularly Japanese, descent. Clinically, it is characterized by multiple asymptomatic red-brown plaques and nodules on the trunk. Lymphadenopathy and hypergammaglobulinemia may be present. Histologically, the lesions show a moderately dense superficial and deep perivascular infiltrate composed predominantly of mature plasma cells without atypia or light chain restriction. We report our experience with five additional cases, including results of immunohistochemical studies for human herpes virus 8.

Keratosis lichenoides chronica mimicking verrucous secondary syphilis

Keratosis lichenoides chronica is a rare dermatosis of unknown etiology with a wide variety of cutaneous manifestations. We present a 47-year-old male with a history of progressive and recalcitrant hyperkeratotic and warty plaques, mimicking verrucous secondary syphilis both clinically and microscopically. We review the clinical manifestations, microscopic features, and treatment modalities for this rare and distinctive dermatosis.