Proliferating Pilar Tumor Clinical Presentation

Updated: Jan 27, 2020
  • Author: Marjon Vatanchi, MD; Chief Editor: William D James, MD  more...
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Patients usually report a slowly or rapidly enlarging nodule. Patients may give a history of recent trauma to the site. The nodule may have been present for months to years without symptoms.


Physical Examination

Lesions usually are single, firm-to-soft, painless nodules. However, there is a case report of multiple benign proliferating pilar tumors occurring in a single patient over a period of 20 years in several anatomic regions, including the gluteal region, groin, perineum, bilateral axillae, face, and neck. [11]

The size may range from 1-10 cm, although lesions as large as 25 cm have been reported.

Inflammation, ulceration, bleeding, and/or yellowish discharge may occur.

The most common (90%) location is the scalp. Other reported sites include back, chest, axilla, groin, gluteal region, [12] thigh, vulva, [13] , face, and eyelid. [14]



The lesions are usually painless. Exophytic growth with ulceration and foul-smelling discharge may occur. Some lesions may grow very large and cause pressure necrosis on underlying tissues, especially on the scalp. Local recurrence following excision and/or metastasis has been reported in rare instances in which malignancy has occurred. While proliferating pilar tumors (PPTs) may have varying levels of cellular atypia on histologic examination, there have been cases of squamous cell carcinomas diagnosed within PPTs, with one reported case of squamous cell carcinoma progressing to distant nodal metastasis and death. [15]

Case reports have described PPTs that displayed intracranial extension and cases of metastases to the pancreas or lungs. [16, 17] While rare, patients can also have multiple lesions or have secondary changes such as ulceration. [18]