A Rare Tumor of the Diaphragm: Pleomorphic Rhabdomyosarcoma

Pleomorphic Rhabdomyosarcoma: A Systematic Review with Outcome Analysis and Report of a Rare Abdominal Wall Lesion

Introduction. Pleomorphic rhabdomyosarcoma (RMS) is an aggressive and rare malignant neoplasm with a poor prognosis. As its name suggests, this tumor exhibits extensive pleomorphism with features of skeletal muscle differentiation. Due to its rarity, its diagnosis is often a clinical and pathological challenge. Since only small case series and a few scattered case reports exist in the literature, the impact of different demographic features, tumor site, and/or treatment modality on patient outcomes has yet to be extensively studied. Methods. We report a case of a pleomorphic RMS presenting atypically as an abdominal wall mass. We have also analyzed the National Cancer Institute's Surveillance, Epidemiology and End Results (SEER) database to determine the factors affecting the outcome of this neoplasm. Moreover, we present a review and summary of pleomorphic RMS cases arising from the abdominal wall reported in the English language literature. Results. We found two hundred and forty-two cases of pleomorphic RMS in the SEER database. The majority of the patients were diagnosed after the age of 40, with the age of diagnosis showing a unimodal distribution. The majority of the patients were Caucasian (82%) and male (59%). Age of diagnosis, tumor stage, and surgical management significantly affected the patients' outcome, while patients' ethnicity, sex, or tumor site did not affect the outcome. We only found five previously reported cases of pleomorphic RMS arising from the abdominal wall. Conclusions. Pleomorphic RMS arising from the abdominal wall is extremely rare. Our data sheds light on the factors affecting the outcome of pleomorphic RMS. We have also discussed the challenges involving the histopathological diagnosis of this rare neoplasm and how to best approach this task.

Primary diaphragmatic undifferentiated pleomorphic sarcoma in a cat

Case summary

A 5-year-old neutered female domestic shorthair cat was referred for acute onset of dyspnoea. Thoracic radiographs performed by the referring veterinarian revealed the presence of pleural effusion. Upon presentation, the cat was dyspnoeic, and cardiopulmonary auscultation revealed muffled heart sounds and bilaterally increased bronchovesicular sounds. Radiographic study of the thorax revealed bilateral pleural effusion and a soft tissue opacity in the dorsocaudal region of the left hemithorax. A whole-body contrast-enhanced CT scan identified a soft tissue mass arising from the left diaphragmatic crus. Transthoracic ultrasound-guided fine-needle aspiration (FNA) of the mass was performed and the result was consistent with a malignant mesenchymal neoplasia, showing giant cells. Cytoreductive surgery was performed and the histopathology diagnosis of undifferentiated pleomorphic sarcoma was made. Adjuvant chemotherapy was then offered. Ten days after surgery pleural effusion recurred. Thoracic echography revealed the presence of a diaphragmatic thickening in the area of surgical resection. FNA of the thickening was consistent with mesenchymal neoplasia. Even when chemotherapy and supportive treatment with pain relief was instituted, the clinical condition of the cat worsened within a few days and it was euthanased 1 month after surgery.

Relevance and novel information

Primary diaphragmatic tumours (PDTs) have been rarely reported in human and in veterinary medicine, where only three cases have been described in the dog. To our knowledge, this is the first report to describe a PDT, specifically an undifferentiated pleomorphic sarcoma, in a cat.

Primary rhabdomyosarcoma of the diaphragm: case report and review of the literature

BACKGROUND

Diaphragmatic sarcomas are extremely rare and mostly described in children. We present the case of an adult with rhabdomyosarcoma of the diaphragm.

METHODS

We performed a literature review, highlighted possible diagnostic pitfalls, and discussed multidisciplinary treatment options.

Tumors of the diaphragm

Primary tumors of the diaphragm are rare. The most common benign cystic lesions of the diaphragm are bronchogenic or mesothelial cysts, while the most common benign solid lesion is a lipoma. Benign tumors of the diaphragm are resected if they are symptomatic or if there is a doubt about the diagnosis. The most common primary malignant lesion is rhabdomyosarcoma. Malignant tumors are treated based on histology and often with chemotherapy and/or radiation along with surgical resection if feasible. Endometriosis, a benign process that metastasizes to the diaphragm, is typically treated medically; surgical ablation or resection is considered only after failed conservative treatment. Surgical resection of metastatic malignant tumors, such as ovarian cancer and thymoma, as well as malignancies affecting the diaphragm by direct extension, such as mesothelioma, lung, and esophageal cancer, may provide some survival advantage.