Beyond the Surface of Giant Pilomatricoma: A Rare Skin Tumor with Unique Clinical and Histological Findings: A Review

Abstract

Purpose of the Review: Pilomatricoma, also known as calcifying epithelioma of Malherbe, is a rare benign skin tumor that arises from the hair follicles. This tumor rarely presents with significant dimensions and is called giant pilomatricoma, which can be challenging to diagnose. Surgical excision for both diagnostic and therapeutic purposes is often necessary. This review summarizes this rare entity's histopathological findings and surgical approaches that often mimic pilomatrix carcinoma, thereby providing specialized physicians with a comprehensive and extensive educative tool regarding this topic. Recent Findings: In our article, we gave updated insights on 42 cases of giant pilomatricomas. Our calculations based on the 53 reported lesions have shown that these giant pilomatricomas have a 33% predominance in age groups 31–50, a 43% localization in the head and neck area, and the growth rate has been computed to be 1 cm every 16 months. Giant pilomatricomas could be confused for pilomatrix carcinoma, highlighting the need of adequate histological evaluation and imaging modalities described thoroughly in the article. Surgical resection remains the main treatment, with several closure options detailed. Summary: Pilomatricoma, a rare skin neoplasm, typically appears on the head, neck, and upper trunk. Occasionally, it can develop into a giant tumor exceeding 5 cm, resembling pilomatrix carcinoma. Despite initial clinical suspicions, confirmation of its benign nature requires total resection and histopathological evaluation. Imaging aids in distinguishing between benign and malignant forms. Histopathological features include cystic lesions, basaloid cells, fading central nuclei, ossifications, transitional cells, and giant multinucleated cells. Surgical resection is necessary as these tumors do not regress spontaneously. Closure options post-resection include local rotational flaps, split-thickness skin grafts, and pedicled deltopectoral rotational flaps, with collaboration with a plastic surgery team for larger defects. Primary closure may be considered based on adjacent skin laxity.