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.