Viral-Associated Trichodysplasia Spinulosa: A Case with Electron Microscopic and Molecular Detection of the Trichodysplasia Spinulosa-Associated Human Polyomavirus

In 2011, researchers reported a case of Trichodysplasia spinulosa (TS), a rare skin condition linked to immunosuppression, in a 7-year-old girl with Down syndrome and pre-B-acute lymphoblastic leukemia who was undergoing chemotherapy. The patient's hair follicles were abnormally dilated due to a proliferation of inner root sheath cells with enlarged cytoplasmic granules, leading to keratotic debris and small hair shaft-like material. Electron microscopy revealed viral particles consistent with a polyomavirus in the follicular debris. DNA PCR and gene sequencing confirmed the presence of the Trichodysplasia spinulosa-associated human polyomavirus (TSPyV), while tests for Merkel cell polyomavirus were negative. This case was significant as it was the first instance of TS confirmed by electron microscopy where the associated virus was molecularly identified. The paper also reviewed an additional 19 cases that could be classified as TS.