Multiple Papules and Nodules in a Dermatomal Distribution: A Quiz
Clinical Summary
View sourceWhat was studied
A single 37-year-old man with multiple flesh‑colored, soft papules and nodules in a unilateral dermatomal pattern on the right lumbar region underwent dermoscopy and deep‑shave biopsy with immunohistochemistry.
Key findings
Histology showed a dermal proliferation of spindle cells with scant pale cytoplasm and wavy nuclei in a collagenous stroma; tumor cells were pS100‑positive and Melan‑A, EMA, and CD57 negative, consistent with cutaneous neurofibroma. Given the dermatomal clustering and absence of other NF features, the diagnosis was segmental neurofibromatosis.
Study limitations
Single‑patient case; no follow‑up or treatment outcomes reported.
Clinical implications
When multiple soft, flesh‑colored papules or nodules cluster within one dermatome, consider segmental neurofibromatosis; biopsy showing S100‑positive spindle cells supports cutaneous neurofibroma. After excluding other NF1 signs, reassure about localized disease, counsel on the small hereditary risk with gonadal mosaicism, and consider surgical excision for large painful or disfiguring lesions.
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