Bullous Pilomatricoma: A Rare Variant Resembling Bouncy Ball
A 17-year-old girl presented with a solitary reddish semi-transparent blister over her right upper arm since 3 months. Initially, the lesion started as a solid pin-head sized papule, which gradually progressed to form a semi-transparent blister with a hard nodule inside. No history of local trauma or insect bite. No history of similar lesions in the past or in family members.\nOn examination, single 2 cm sized erythematous semi-transparent bullae with a white nodule was seen on the medial aspect of the right upper arm [Figure and ]. The appearance of this resembled a bouncy ball []. On palpation, the bullae had a jelly like consistency and the nodule underneath was hard. On puncturing the lesion, it oozed a jelly like material. Systemic examination was normal. We considered a differential diagnosis of infected sebaceous cyst and dermatofibroma.\nRoutine investigations were normal and excision biopsy was carried out []. Histopathology revealed islands of basaloid cells with central abrupt keratinization and dilated lymphatics with dermal edema [Figures and ]. Ghost cells (shadow cells) [], foreign body giant cell reaction [], and small foci of calcification were also seen []. With these findings, diagnosis of bullous pilomatricoma was made.