A 61-year-old male presented with pain during defecation and occasional bleeding per rectum over 2 months. Pain was nonradiating, dull aching, and persistent. Pain increased with constipation. Bleeding was frank red and came as drops after passage of stool. There was no tenesmus. There was no dizziness, weakness, pica, or weight loss. There was no significant relief with medication.
The patient was not a known case of piles/diabetes mellitus/hypertension/tuberculosis/or any other chronic ailment. The patient was a known alcoholic and smoker. He had no urinary complaints. There were no other complaints referable to chest and cardiac or nervous system.
He was a heterosexual with no known drug allergies.
On examination he was moderately built and of average nourishment. Karnofsky performance scale was more than 80. There was no pallor/icterus/pedal edema/lymphadenopathy. On digital rectal examination, a hard indurated nontender mass was felt from 2 o'clock to 9 o'clock, starting from the anal verge. The mass had a bosselated surface, and the overlying mucosa was tethered. The upper border of the mass could not be reached. No inguinal, iliac, para aortic, or supraclavicular lymph nodes were palpable.
His hematological and biochemical parameters were all within normal limits, and he was HIV seronegative. His transrectal ultrasound revealed an enlarged prostate with insignificant postvoid residual urine. There was significant ill-defined mural thickness and hypervascularity along anorectal canal causing indentation of prostate. CT scan of the abdomen and pelvis showed an endo-exophytic soft tissue mass at anorectum suggestive of mitotic pathology. MRI pelvis revealed a lesion involving rectum and anal canal with extension into intersphincteric plane and puborectalis (Figures 1 and 2). His colonoscopy was suggestive of anorectal carcinoma, and colonoscopy guided biopsy was suggestive of spindle cell carcinoma. A repeat punch biopsy was suggestive of leiomyosarcoma.
The patient underwent abdominoperineal resection with end colostomy (Figures 3 and 4). Histopathological examination report revealed anal canal GIST with tumor size more than 5 cm in maximum dimension. Mitotic figures were more than 5/50 HPF. Proximal and distal resected margins were uninvolved by tumor. Circumferential resected margin was less than 0.1 cm away from tumor. There was no lymphovascular invasion. Out of the 6 lymph nodes resected none were involved by tumor. The CD117:immunoreactive score:was 3+ in spindled cells (Figures 5 and 6).