A 61-year-old male was admitted to the Clinic for Infectious Diseases "Dr. Fran Mihaljevic", Zagreb, Croatia, in July 2019, presenting with a fever of 39 C, accompanied with night sweats, vomiting, and pain in the lower left abdomen during a period of one month. Past medical history included arterial hypertension controlled by amlodipine. Routine blood tests showed elevated inflammatory markers (CRP 136-165 mg/L, SE 100 mm/h, leucocytes 8.7 x 109/L). The patient was treated with multiple antibiotics (azithromycin, clarithromycin, ceftriaxone, cloxacillin, ciprofloxacin, vancomycin, and meropenem) and tested negative for a number of infectious diseases (hemorrhagic fever with renal syndrome, Q fever, brucellosis, Bartonella, and tuberculosis). Tests for tumor markers (CEA, CA19-9, AFP, and PSA) were negative. A multislice computed tomography (MSCT) scan with contrast of the thorax, abdomen, and pelvis revealed multiple expansive, hypovascularized soft tissue tumors up to 4 cm in diameter in the region of the left iliopsoas and gluteus medius muscles.
17 days after initial hospitalization, the patient presented with hematochezia and was subsequently transferred to the Sestre Milosrdnice University Hospital Center, Zagreb, Croatia, where a colonoscopy was performed, which found an ulcerated, hemorrhagic subepithelial tumor in the sigmoid colon. Specimens of the lesion were taken for microscopic examination. Resection of the rectosigmoid colon with colorectal anastomosis was performed (Figures 1(a) and 1(b)).
H&E stained slides of the sample taken during colonoscopy revealed polymorphic, poorly differentiated tumor cells. Immunohistochemistry found the tumor cells to be positive for CD117, SMA, and S-100, while negative for CD34, chromogranin A, CK7, CK20, PAN-CK, HMB45, synaptophysin, and PAX-8. A preliminary diagnosis of poorly differentiated gastrointestinal stromal tumor (GIST) was given.
Gross pathological examination of the resected colon segment and surrounding fat tissue revealed four separate tumors. One tumor was the ulcerated lesion seen and biopsied during colonoscopy, measuring 2 cm in greatest diameter, while the remaining three were hemorrhagic nodules ranging from 0.6 cm to 2 cm in diameter, located in the surrounding fat tissue.
Microscopically, H&E sections of all tumors showed seemingly solid sheets of spindle and epithelioid neoplastic cells with irregular nuclei, prominent nucleoli, and numerous mitotic figures. At higher magnification, fissures between the neoplastic cells containing erythrocytes could be discerned. Immunohistochemical analysis performed on samples of the largest nodular tumor revealed that the neoplastic cells were positive for ERG, CD31, CD34, vimentin, and CD117, while negative for CK7, CK20, CD20, CD3, CD45, TTF-1, PAN-CK, ALK, Mpox, S-100, and DOG1 (Figures 2(a)-2(d)). The Ki-67 index was over 90%, indicating exceedingly high proliferative activity. The final pathological diagnosis was that of multiple primary colonic angiosarcomas.
The patient's overall condition declined significantly following surgery. A CT scan showed multiple residual tumors in the lower abdomen and pelvis measuring up to 6.5 cm in the greatest diameter, with signs of massive hemorrhage within them (Figures 3(a)-3(d)). The patient passed away from multiple organ failures in September 2019, 60 days after initial hospitalization. An autopsy was not performed.