Pilomatrixoma is a rare benign tumor. Several special types of pilomatrixomas have been discovered, e.g. bullous pilomatrixoma and perforating pilomatrixoma. Here, we reported one of its special types. A 14 y old Chinese girl presented to our hospital with a six-month history of cystic mass on her right upper arm after a mosquito bite. A histopathological diagnosis was pilomatrixoma after complete surgical resection. The dilated lymphatic vessels are rare in the blister structure, thus, we used the term "pseudobullous" to describe the variant of pilomatrixoma in this case. The lesion of patient has no recurrence with follow-up for 1 y. The regular follow-up is required after excision, as rare cases with potential malignant transformation and recurrence have been reported.