A 26-year-old woman is referred for evaluation of a bump under the skin of her left hand. The lesion has been slowly increasing in size over the course of a year. The patient denies previous trauma to the area and states the lesion is asymptomatic. Her medical history is unremarkable. Physical examination reveals a solitary, firm, flesh-colored papule. Light palpation does not elicit tenderness. No similar lesions are noted elsewhere.
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Punch biopsy was performed, and histopathologic examination revealed a palisaded encapsulated neuroma (PEN). PEN is a benign cutaneous neoplasm that typically presents as a painless, dome-shaped papule or nodule. Lesions typically appear on the face but may also affect the extremities, trunk, and genital region. Although usually solitary, PEN may present as multiple lesions.1
PEN typically affects patients aged 40 to 60 years and has slight predilection for women compared with men.2 Clinically, lesions may resemble schwannoma, neurofibroma, or nodular basal cell carcinoma.2 PEN is not associated with underlying systemic disease or malignancy.2 Initially thought to be a component of multiple endocrine neoplasia type 2B, PEN is now considered a unique entity with uncertain pathogenesis.3
Curative treatment of PEN is achieved through surgical excision. These lesions have no known propensity for recurrence or malignant transformation, thus reducing the need for unnecessary testing or concern for malignancy or systemic disease.4,5
Nelson Maniscalco, DPM, is a joint podiatry/dermatology fellow under the aegis of St. Luke’s Medical Center in Allentown, Pennsylvania, and the DermDox Center for Dermatology. Stephen Schleicher, MD, is director of the DermDox Center for Dermatology, associate professor of medicine at Commonwealth Medical College, and clinical instructor of dermatology at Arcadia University and Kings College.
1. Beutler BD, Cohen PR. Palisaded encapsulated neuroma of the trunk: a case report and review of palisaded encapsulated neuroma. Cureus. 2016;8(8):e726.
2. Newman MD, Milgraum S. Palisaded encapsulated neuroma (PEN): an often misdiagnosed neural tumor. Dermatol Online J. 2008;14(7):12.
3. Leblebici C, Savli TC, Yeni B, Cin M, Aksu AEK. Palisaded encapsulated (solitary circumscribed) neuroma: a review of 30 cases. Int J Surg Pathol. 2019;27(5):506-514.
4. Tiwary AK, Chaudhary SS, Mishra DK. Palisaded encapsulated neuroma: an uncommon tumour at uncommon location. Our Dermatol Online. 2016;7(4):442-444.
5. Batra J, Ramesh V, Molpariya A, Maan KK. Palisaded encapsulated neuroma: an unusual presentation. Indian Dermatol Online J. 2018;9(4):262-264.