Diagnostic evaluation of metastatic rhabdomyosarcoma in effusion specimens

Abstract

Sarcomas, including rhabdomyosarcoma (RMS), are rarely encountered in effusion specimens; therefore, difficulties in the accurate diagnosis of metastatic sarcomas in effusions can occasionally arise. Immunohistochemistry for myogenin has emerged as a useful adjunct in the diagnosis of RMS, especially in small biopsy specimens. To date, there are no published series describing the utility of immunocytochemistry for myogenin in the diagnosis of RMS in effusion specimens. A total of 15 patients, for whom metastatic sarcomas were diagnosed in effusion specimens between 1998 and 2012, were identified for analysis: alveolar RMS (n = 5); embryonal RMS (n = 1); pleomorphic RMS (n = 1); angiosarcoma (n = 1); Ewing's sarcoma (n = 2); osteosarcoma (n = 1); endometrial stromal sarcoma (n = 1); unclassified spindle cell sarcoma (n = 1); unclassified/undifferentiated pleomorphic sarcoma (n = 1); and leiomyosarcoma (n = 1). Immunocytochemistry for myogenin was performed for each of these cases as well as for 102 effusions that were positive for metastatic carcinoma. Immunocytochemistry for myogenin diffusely and strongly highlighted the nuclei of the tumor cells in six (86%) of seven cases of metastatic RMS; specifically, the five alveolar RMS and one embryonal RMS cases. The one case of pleomorphic RMS, the eight remaining metastatic sarcoma cases, and all 102 cases of metastatic carcinoma were completely negative for myogenin expression. In conclusion, immunocytochemistry for myogenin is a sensitive and specific ancillary adjunct in the diagnostic evaluation of metastatic RMS in effusion specimens.

Bone and soft tissue sarcomas in cerebrospinal fluid and effusion: A 20‐year review at our institution

“…The predominance of round cells in most of our RMS cases was similar to the findings of prior publications concerning this entity in fluid cytology 3,6‐8 . However, some publications have also described the presence of an epithelioid and reactive, mesothelial‐like morphology easily mimicking other types of malignancy 9,10 . Our cases of Ewing sarcoma showed features very similar to those of RMS, and we found it extremely difficult to differentiate them on cytology alone.…”

“…3,[6][7][8] However, some publications have also described the presence of an epithelioid and reactive, mesothelial-like morphology easily mimicking other types of malignancy. 9,10 Our cases of Ewing sarcoma showed features very similar to those of RMS, and we found it extremely difficult to differentiate them on cytology alone. Our findings are concordant with the results of a study by Ikeda and Tsuta, 11 who used a microscope digital camera device to evaluate the lengths of nuclei, cytoplasm, and cell cluster areas of 40 small round cell tumors.…”

Cytomorphology of NUTM1‐rearranged sarcoma involving pleural fluid

“…Because many of the tumor cells displayed rhabdoid morphology in our case, rhabdomyosarcoma enters the differential diagnosis. Rhabdomyosarcoma, particularly alveolar rhabdomyosarcoma, when involves pleural fluid, can show epithelioid morphology 12 . In LBC specimens, the tumor cells can have plasmacytoid morphology with condensed perinuclear cytoplasmic globules.…”

“…Rhabdomyosarcoma, particularly alveolar rhabdomyosarcoma, when involves pleural fluid, can show epithelioid morphology. 12 In LBC specimens, the tumor cells can have plasmacytoid morphology with condensed perinuclear cytoplasmic globules. However, these globules are not specific to rhabdomyosarcomas and are also identified in fluids involved by other sarcomas, such as angiosarcoma.…”

Exfoliation of Alveolar Rhabdomyosarcoma Cells in the Ascites of a 50-Year-Old Woman: Diagnostic Challenges and Literature Review

“…Myogenin is particularly useful because its expression in ARMS is stronger than in ERMS, which allows the two subtypes to be distiguished 14,15 . A previous study reported that myogenin was expressed in 86% of ARMS cases 9 . In the present type, but were unable to do so because hysterectomy was not performed, which is a limitation of this study.…”