Abstract Onychocytic matricoma is a newly described tumor of the nail matrix. Clinically, it presents with localized thickening of the nail plate and melanonychia. Histologically, it represents a benign acanthoma of onychocytes. There are 8 cases reported in the literature. A 12-year-old girl presented with localized melanonychia and concurrent thickening of the nail plate restricted to the area of pigmentation affecting the right thumb, with no history of trauma or pain. We report a case of this rare tumor occurring in late childhood and provide a comprehensive review of its clinical presentation and differential diagnosis. Both clinicians and dermatopathologists should be aware of the presentation of onychocytic matricoma and include it in their scope of diagnosis of longitudinal nail bands.

Immunobiologic therapy is indicated for severe forms of psoriasis, resistant to conventional therapy. There is growing concern about their safety profile and possible association with cancer development. This article documents two cases of renal cell cancer during treatment with biologic therapy, reviewing what is described in the literature . The risk of solid tumors as a complication of using TNF-alpha inhibitors is controversial. No conclusion can be drawn from the data in the literature, however, we believe that special attention should be given to those with known risk factors for a specific neoplasm.