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

Gastric Leiomyosarcoma in Post-Gastrointestinal Stromal Tumor Era: Revisit

Primary gastric leiomyosarcoma is an exceptionally rare disease. This review covers 41 post-gastrointestinal stromal tumor (GIST) era gastric leiomyosarcoma cases that are supported by immunohistochemistry markers. Other spindle cell lesions are also excluded through histological and immunohistochemistry evaluations. The patients range from 3 to 82 years old, with an average age of 54.6 years. The male-to-female ratio is 1.4:1, from diverse geographic areas. Patients may experience abdominal symptoms, and tumor sizes vary between 1 cm and 22 cm. Morphologically, tumors originate from the muscularis propria or the muscularis mucosae, well-circumscribed with spindle cells arranged in fascicule. Tumoral cells exhibit positivity for smooth muscle markers while being negative for GIST markers and others. The mitotic index ranges from 2 to 500/50 high power field. Ki-67 index varies from 15% to 70%. Management typically involves gastrectomy and other appropriate treatments, with tumor recurrence being uncommon. 56% of patients are alive, with 5 patients dying from this disease. Statistical analyses conducted on post-GIST era cases reveal that a mitotic index of ≥100/50 high power field, tumor recurrence, metastasis, or positive lymph nodes significantly correlate with prognosis.

Primary omental smooth muscle tumor in an adult male: a diagnostic dilemma for leiomyoma: a case report

BACKGROUND

The greater omentum comprises peritoneal, adipose, vascular, and lymphoid tissues. Most omental malignancies are metastatic tumors, and the incidence of primary tumors is rare. We report on a prior omental smooth muscle tumor case in an adult male patient.

CASE PRESENTATION

A 54-year-old Japanese male patient with no relevant medical history was diagnosed with an abdominal mass during a routine medical checkup. Subsequent contrast-enhanced computed tomography revealed a mass of approximately 3 cm in size in the greater omentum, and a laparotomy was performed. A 27 × 25 × 20 mm raised lesion was found in the omentum. Microscopically, spindle cells were observed and arranged in whorls and fascicles. Individual tumor cells had short spindle-shaped nuclei with slightly increased chromatin and were characterized by a slightly eosinophilic, spindle-shaped cytoplasm. The mitotic count was less than 1 per 50 high-power fields. The tumor cells showed positive immunoreactivity for α smooth muscle actin, HHF35, and desmin on immunohistochemical examination. The Ki-67 labeling index using the average method was 1.76% (261/14806). No immunoreactivity was observed for any of the other tested markers. We considered leiomyoma owing to a lack of malignant findings. However, primary omental leiomyoma has rarely been reported, and it can be difficult to completely rule out the malignant potential of smooth muscle tumors in soft tissues. Our patient was decisively diagnosed with a primary omental smooth muscle tumor considering leiomyoma. Consequently, the patient did not undergo additional adjuvant therapy and was followed up. The patient was satisfied with treatment and showed neither recurrence nor metastasis at the 13-month postoperative follow-up.

DISCUSSION AND CONCLUSION

We encountered a primary smooth muscle tumor of the greater omentum with no histological findings suggestive of malignancy in an adult male patient. However, omental smooth muscle tumors are extremely difficult to define as benign, requiring careful diagnosis. Further case reports with long-term follow-up and case series are required to determine whether a true omental benign smooth muscle tumor (leiomyoma) exists. In addition, proper interpretation of the Ki-67 labeling index should be established. This case study is a foundation for future research.

Leiomyosarcoma of stomach extending to gastroesophageal junction and distal esophagus as a rare cause of dysphagia: a case report

Introduction and importance

Gastric leiomyosarcoma is a rare malignant tumor among the primary gastric carcinomas. Among the different common presentations, dysphagia is an uncommon presentation of gastric leiomyosarcoma.

Case presentation

A 29-year-old female presented with complaints of progressive dysphagia for 1 year associated with vomiting, significant weight loss, and anorexia for 6 months. On blood investigations, she had anemia, hypokalemia, prerenal acute kidney injury, and unconjugated hyperbilirubinemia. Upper gastrointestinal endoscopy and contrast-enhanced computed tomography (CECT) were initially suggestive of carcinoma of stomach. Immunohistochemistry was diagnostic of leiomyosarcoma of stomach extending to the gastroesophageal junction and distal esophagus. She underwent total gastrectomy with distal esophagectomy with lateral segmentectomy of liver (nonanatomical) with Roux-en-Y esophago-jejunal anastomosis (end-to-side and retro-colic) through thoracoabdominal approach. After 6 weeks, she received four cycles of doxorubicin therapy. Follow-up at 18 months after surgery revealed no recurrence of malignancy.

Clinical discussion

Leiomyosarcoma, a rare malignant tumor arising from stomach involves commonly gastric body followed by antrum and fundus. Imaging including CECT and tissue diagnosis including immunohistochemistry (positive for α-SMA, desmin, calponin, h-caldesmon, or smoothelin) have been mainstay for definitive diagnosis. The standard treatment for leiomyosarcoma of stomach is complete surgical resection of tumor because it has malignant potential and does not respond to targeted treatment with a tyrosine kinase inhibitor. The type of surgery depends on the size and localization of the tumor.

Conclusions

Early diagnosis with proper imaging, immunohistochemistry, and biopsy play important role in differentiating gastric leiomyosarcoma from gastrointestinal stromal tumor. Surgical resection is the mainstay of treatment.

Natural history of gastric leiomyoma

BACKGROUND

Most gastric leiomyomas are asymptomatic and benign subepithelial tumors (SETs); however, some may increase in size or become symptomatic. Understanding their natural history is therefore important to their management. We investigated the natural history of histologically proven gastric leiomyomas.

METHODS

We retrospectively reviewed histologically proven gastric leiomyoma cases at a tertiary center. The baseline characteristics of these cases were analyzed, and those with a follow-up period of at least 12 months without immediate resection were evaluated. The primary outcome was the frequency of size increase of more than 25% during the follow-up period, and the secondary outcome was the histopathologic results in cases that underwent resection.

RESULTS

Among the 231 patients with histologically proven gastric leiomyomas, the most frequent location was the cardia (77.1%), and the median size was 3 cm (IQR 2-4 cm). Eighty-four cases were followed up over a median period of 50.8 months (IQR 27.2-91.3 months). During the follow-up period, tumor size increased in two cases (2.4%). Surgical results showed that one case was leiomyoma, and the other was leiomyosarcoma. Among the remaining cases without change in size, 15 underwent surgical resection (n = 10) or endoscopic resection (n = 5), and all cases were confirmed as leiomyoma.

CONCLUSIONS

Most gastric leiomyomas are benign SETs, and an increase in size is not frequent, even in large-sized cases. Close monitoring with routine follow-up without resection may be sufficient in cases of histologically proven gastric leiomyoma. However, in cases of ulceration or size increase, resection may be beneficial.

Endoluminal Leiomyoma of the Gastric Antrum: a Report of a Rare Case

Endoluminal gastric leiomyoma (GL) of the antrum is a rare benign tumor. In this paper, we report a case of a 72-year-old patient that presented for a 1-month episode of epigastric pain. Imaging found a well-limited tumor in the antrum with extrinsic compression on ulcerated congestive mucosa. A surgical resection based on Finsterer's antrectomy with end-to-side trans-mesocolic gastro-jejunal anastomosis was performed. The histopathological examination in combination with immunohistochemistry diagnosed GL and found a diffuse and marked staining of smooth muscle actin (SMA) and h-caldesmon (h-CD) and negative expression of CD117 and DOG1. The patient was discharged without post-surgical complications and is still alive at the time of this case report writing.