Anal leiomyosarcoma: A case report and review of literature

Abstract

Introduction: Leiomyosarcoma is a malignant neoplasm that is derived from smooth muscle cells in walls of small blood vessels or branch of the inferior vena cava, the uterus and the gastrointestinal tract. Different treatment options are present for the treatment of LMS. However, due to the rarity of LMS, the optimal treatment option is still to be discussed and determined.

Presentation of case: A 51-year-old male patient, previously healthy, presented for perianal pain. Biopsy of the mass found showed spindle cell tumors with mild atypia, dense cellularity, and pelvic MRI with contrast showed a well-circumscribed mass of the anus, developed between the layers of the external sphincter with possible invasion of the internal sphincter consistent with Leiomyosarcoma Grade I. Wide excision was performed. Close follow-up should be done every 3 to 6 months for the first 2 to 3 years, every 6 to 12 months for the following 3 years, and annually afterwards.

Discussion: The symptoms of LMS include rectal bleeding with rectal and/or abdominal pain, weight loss, constipation, altered bowel motion and protruding mass. Treatment options include wide local excision, abdominoperineal resection, low anterior resection, bloc resection and pelvic exenteration. Patients who underwent wide local excision show a higher local recurrence rate as compared to patients who underwent radical resection. Distant metastasis is higher in patients who underwent radical resection.

Conclusion: The treatment options of anal LMS are controversial. At present, very few cases have been reported, thus no universally accepted standard of surgical treatment has been established.

Keywords: Abdominoperineal resection; Anal; Case report; Excision; Leiomyosarcoma; Sarcoma.

Fig. 1

Perianal area of the 51-year-old male patient, showing mass with no pus.

Fig. 2

Anal Leiomyosarcoma in 51-year-old male patient, previously healthy presented for perianal pain. Axial contrast-enhanced T1-weighted MR image shows an well-defined anal mass (arrow) in contact with the internal and external anal sphincters. This mass shows homogenous contrast enhancement with eccentric heterogeneous component.

Fig. 3

Post operative resection of anal leiomyosarcoma. Axial T1-weighted MR image shows residual hemorrhagic component in the posterior inter-sphincteric region (post operative changes).

Fig. 4

Surgery done – sphincteroplasty, penrose insertion in the wound and anal packing.

Fig. 5

Axial contrast-enhanced T1-weighted MR image showing mild residual inflammation at the surgical bed of the posterior aspect at 6 o'clock of the anal canal.