Progressive nodular histiocytosis

Progressive Nodular Histiocytosis: Report of a Case and Review of the Literature

Progressive nodular histiocytosis (PNH) is a rare condition characterized by progressive eruption of multiple yellowish-brown papules and nodules on the skin and mucous membranes. We present the case of a 37-year-old Caucasian man with gradually increased appearance of nodular lesions on the forehead and right temple. These lesions were initially diagnosed as xanthomas and did not respond to intralesional injections of triamcinolone. Additional biopsy revealed an intense dermal infiltrate of foamy mononuclear epithelioid cells with a minor admixture of plasma cells, lymphocytes, and scattered multinucleated giant cells. On immunohistochemical staining, the lesional cells were positive for CD163 and CD68 and negative for CD1a, thus confirming a mononuclear-macrophage lineage. The clinical presentation and the histological impression lead to the diagnosis of PNH. This condition could be challenging, mimicking microscopically similar lesions of the non-Langerhans cell histiocytosis group. Although uncommon, PNH stands out due to its clinical and microscopic features and should be taken into consideration in the differential diagnosis of cutaneous histiocytoses.

Scleromyxedema histopathologically mimicking hypercellular fibrous papules (angiofibomas): Case report of an unusual histopathological presentation

Scleromyxedema (SMX) is an inflammatory condition of unknown etiology strongly associated with monoclonal gammopathy. Classical histopathology of SMX is characterized with the triad of diffuse mucin deposits, increased amount of collagen, and presence of stellate fibroblasts. Herein, we report an unusual histopathological variant of SMX in a 41-year-old female with lesions of the nose histopathologically mimicking cellular angiofibromas. The dome-shaped papules were characterized by increased collagen bundles and fascicles of spindle cells. Widened vessels were seen at the periphery of the proliferation. Cells expressed CD68. Factor XIIIa was expressed only by dendritic cells. The mucin was highlighted with colloidal iron. In sum, we draw attention to this unusual variant of SMX, which should be suspected in a setting of multiple "angiofibromas/fibrous papules" on the face with presence of mucin.

Laryngeal involvement with fatal outcome in progressive nodular histiocytosis: A rare case report

Progressive nodular histiocytosis (PNH) represents a very rare type of non-Langerhans cell histiocytosis. It is characterized by progressive appearance of papules and nodules without spontaneous resolution. We report a 60-year-old patient with novel clinical features in the form of extensive noduloulcerative lesions, ichthyotic patches, and laryngeal involvement culminating in fatal outcome prior to therapeutic intervention. Although the presenting features were baffling, histopathology and immunohistochemistry clinched the diagnosis of PNH.