Leiomyosarcoma of the transverse colon with lymph node metastasis and malignant transformation: a case report

Abstract

Background The concept of GIST was established in 1998, clearly differentiating between gastrointestinal leiomyosarcoma and GISTs among gastrointestinal mesenchymal tumors. Lymph node metastasis is extremely rare in true gastrointestinal leiomyosarcoma, and there are no reports of malignant transformation from leiomyoma. Case presentation The patient was an old woman who had undergone endoscopic mucosal resection for an Is polyp on the left side of the transverse colon at the age of 73. She was diagnosed with leiomyoma with positive surgical margins. Subsequently, she presented to our institution with a sensation of pressure in the upper abdominal region as a chief complaint at the age of 76 years. Abdominal computed tomography and colorectal endoscopy showed a tumor lesion with invagination of the intestines in the transverse colon, the same site as that of the previously resected leiomyoma. A biopsy suggested a smooth muscle tumor, and we performed partial left transverse colectomy and lymph node dissection under a diagnosis of recurrence and enlargement of the previously incompletely resected leiomyoma. Histopathological examination revealed spindle-shaped tumor cells, and the mitotic activity was 30–40/10 high-power field. Tumor cells were immunohistologically positive for α-smooth muscle actin and h-caldesmon; partially positive for desmin; negative for c-kit, CD34, DOG-1, and the S-100 protein; and showed a Ki-67 labeling index of 70–80%. She was diagnosed with leiomyosarcoma malignantly transformed from leiomyoma. Metastasis was found in 1 of the 14 resected lymph nodes. The patient did not undergo adjuvant chemotherapy, but has survived with no recurrence at 2 years after the surgery. Conclusions We have reported a case of leiomyosarcoma of the transverse colon with lymph node metastasis that was malignantly transformed from a leiomyoma.

High grade leiomyosarcoma of the transverse colon with positive lymph node metastasis: to treat or not to treat with adjuvant radiation therapy?

“…Metastasis mainly occurs haematogenously, most commonly to the lungs and liver, and is considered to be incurable; these patients are offered palliative treatment. Metastasis to lymph nodes is extremely rare in true GI LMS, but not considered to be incurable as is the case for distant haematogenous metastasis 12–14. To date, no similar cases of intra-abdominal LMS have discussed the role of radiotherapy.…”

The first case of gastric leiomyosarcoma developed through malignant transformation of leiomyoma

“…They also demonstrated that leiomyosarcoma areas harbored genetic alterations that were found in the corresponding leiomyoma-like areas, and in addition, leiomyosarcoma areas had additional genetic alterations including Myc amplification, loss of foci for RB-1, TP53, etc. Recently, Tago et al 16 reported a case of colonic leiomyosarcoma that highly likely developed through malignant transformation of leiomyoma which was endoscopically resected 3 years ago. This colonic case is the first report of malignant transformation of the gastrointestinal tract, and our gastric case is the first to demonstrate direct transition from leiomyoma to leiomyosarcoma.…”

Giant leiomyosarcoma of the transverse colon

“…The efficacy of preventive lymph node dissection is still controversial. Of all the reported cases on colonic LMS, only two cases have been shown to exhibit lymph node metastasis 15 16…”