Cutaneous plasmacytosis with mast cell infiltration.

Cutaneous plasmacytosis is a rare disorder of uncertain etiology, described mainly in patients of Japanese descent. Clinically, it is characterized by multiple pigmented papules and plaques distributed primarily on the trunk. Histopathologically, it is marked by a dense dermal plasma cell infiltrate. Here, we describe a case of cutaneous plasmacytosis in a 55-year-old Indian male who presented with hyperpigmented plaques on the body. Histopathological examination revealed dense superficial and deep perivascular and periappendageal infiltrate composed mainly of plasma cells, lymphoid follicles with reactive germinal centres, perineural distribution of plasma cells, mast cell infiltration and increased dermal small blood vessels. Immunohistochemical analysis confirmed the polyclonal nature of the plasma cells. Laboratory investigations were within normal limits, except for the presence of polyclonal hypergammaglobulinemia without any M band. There was no evidence of autoimmune disease or any infection. There was no systemic involvement in this patient. The patient was diagnosed as cutaneous plasmacytosis and advised long-term follow-up. Peculiar histopathological finding in this case of cutaneous plasmacytosis was the presence of abundant mast cells in the dermis.

Localized unilateral basaloid follicular hamartoma along Blaschko's lines on face.

Basaloid follicular hamartoma (BFH) is a rare hamartoma of hair follicle. Clinical presentations may vary but are united by the same histopathological features in the form of folliculocentric basaloid or squamoid cell proliferation in the superficial dermis, which represents malformed and distorted hair follicles. It is important to recognize this entity as its simulant is basal cell carcinoma, a low-grade malignancy. Here, we report a case of localized unilateral BFH in a Blaschkoid distribution on the face of a 14-year-old female.