Primary leiomyosarcoma of the greater omentum: a case report

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.

Histopathological Evaluation and Molecular Diagnostic Tests for Peritoneal Metastases with Unknown Primary Site-a Review

Cancer of unknown primary (CUP) is a well-studied entity with guidelines available for the management of patients with CUP. The peritoneum represents one of the metastatic sites in CUP, and peritoneal metastases (PM) could present as CUP. PM of unknown origin remains a poorly studied clinical entity. There is only one series of 15 cases, one population-based study, and few other case reports on this subject. Studies on CUP, in general, cover some common tumour histological types like adenocarcinomas and squamous carcinomas. Some of these tumours may have a good prognosis though majority have high-grade disease with a poor long-term outcome. Some of the histological tumour types commonly seen in the clinical scenario of PM like mucinous carcinoma have not been studied. In this review, we divide PM into five histological types-adenocarcinomas, serous carcinomas, mucinous carcinomas, sarcomas and other rare varieties. We provide algorithms to identify the primary tumour site using immunohistochemistry when imaging, and endoscopy fails to establish the primary tumour site. The role of molecular diagnostic tests for PM or unknown origin is also discussed. Current literature on site-specific systemic therapy based on gene expression profiling does not show a clear benefit of this approach over empirical systemic therapies.

Omental mass combined with indirect inguinal hernia leads to a scrotal mass: A case report

BACKGROUND

Primary omental tumors are uncommon, and omental fibromas account for 2% of these tumors. Due to the low incidence of omental fibromas and the limited relevant literature, it is challenging for clinicians to make an accurate diagnosis of this condition, especially before surgery.

CASE SUMMARY

A 30-year-old man was admitted to the hospital because of a left epididymal mass with vague discomfort for more than 1 mo. A physical examination was performed, and the findings showed that the epididymal mass may have entered the abdominal cavity. Pelvic computed tomography was performed in our hospital and revealed a left inguinal hernia with a mass in the hernial contents, and no masses were found in the left epididymis. A traditional inguinal hernia incision was made. Intraoperative hernia contents were found to be of the greater omentum, and a 2.5 cm-diameter mass was found at the distal end of the greater omentum. The scrotum and epididymis did not exhibit other masses. Then, the mass of the greater omentum was excised. Intraoperative frozen pathological examination suggested a spindle cell tumor. The postoperative pathological examination suggested that the mass was an omental angiofibroma. Postoperatively, the patient recovered well and was discharged. Outpatient re-examinations were performed at 1 mo and half a year after the operation and showed no obvious abnormalities.

CONCLUSION

Due to the low morbidity rate associated with and latent nature of omental tumors, these tumors are difficult to diagnose preoperatively; thorough medical history taking, detailed physical examinations, and necessary imaging auxiliary examinations can help clinicians diagnose and treat these cases.