Leiomyoma Arising From Distal Phalanx of Thumb

Leiomyoma is a benign tumor arise from smooth muscle and distributed wherever smooth muscle is present. Its common elective location is in uterus muscle and limb localization is rare. When it occurs in the extremity, it is more common in the legs, ankle, and foot than it is in the upper extremities. Especially on leiomyoma on the finger tip is extremely rare. This 36-year-old woman presented with a painful mass of the distal phalanx of her left thumb. It was about rice sized movable mass with firm consistency.

The round shaped mass in the left thumb was approximately 0.5×0.4cm in size. It was slowly growing mass without skin color change, bleeding nor ulceration. Under the local anesthesia, The patient underwent surgical excision .The masses were in deep subcutaneous and no connection with right maxillary sinus.

Macrosopic description of the mass is round and encapsuled, grayish nodule with size of 0.5×0.4cm. Microscopic study demonstrated a capsulease lesion of elongated cells white monomorphic cigar-shaped nuclei without atypia. The immunohistological phenotype was positive for Actin, which is marker for smooth muscle, but negative for S-100.

It is extremely rare to find leiomyoma origin from finger tip. Therefore the tumor is difficult to diagnosed before surgery. Only histological study can confirm the diagnosis. Complete surgical excision provides the most effective means of treatment.