Colossal pilomatrixoma

We describe the largest reported case of pilomatrixoma in the literature. While pilomatrixomas typically present as small soft-tissue nodules of the head, neck and upper extremities, they can also present as much larger masses in atypical locations. When they present in their usual size, pilomatrixomas have typical imaging features and can be correctly diagnosed with imaging studies before histological confirmation. Their clinical and imaging diagnosis become challenging when they are very large, as in our case. A giant pilomatrixoma should also be considered for paediatric patients presenting with a large subcutaneous soft-tissue mass.

Giant Pilomatrixoma Presenting in the Posterior Thorax, a Rare Location and the Largest Described

Pilomatrixoma is a common benign soft tissue neoplasm arising from hair follicle cells, typically not exceeding 3 cm and located mainly within the head and neck regions. Lesions greater than 3 cm or those located elsewhere are rare and are often not thought of or high on a differential diagnosis. Moreover, the radiographic features of pilomatrixoma are very nonspecific making the diagnosis even more difficult and rarely described in the radiology literature. We present the largest reported case of pilomatrixoma measuring 24 cm arising from the posterior thorax. Our hope is to increase awareness of this diagnosis for slow-growing soft tissue masses not located in the classically described locations of head and neck, explore the radiographic features on various imaging modalities, and review the current radiology literature.