Prognostic role of pleural effusion or ascites in localized rhabdomyosarcoma

Serous fluid: Metastatic sarcomas, melanoma, and other non-epithelial neoplasms

While most tumors metastatic to the serous membranes are of epithelial origin, cytologists should be aware that non-epithelial neoplasms can also cause malignant effusions including sarcomas, melanomas, germ cell tumors, and, more rarely, brain tumors. The differential diagnosis of a malignant effusion is accordingly broad, especially for the small round blue cell tumors that includes not only mesenchymal tumors, but also non-mesenchymal tumors, such as neuroblastoma and Wilms tumor. Diagnosing non-epithelial malignancies in effusion specimens based entirely upon their cytomorphologic features is difficult because these neoplasms often exhibit considerable morphological overlap and their cytomorphology can differ from the original tumor. As malignant cells have a tendency to round up in body fluids these non-epithelial neoplasms can therefore mimic reactive mesothelial cells and metastatic adenocarcinoma. The use of ancillary studies including immunostaining, FISH, and molecular studies is thus often critical to reach a definitive diagnosis. This review article will be incorporated finally as one of the chapters in CMAS (CytoJournal Monograph/Atlas Series) #2. It is modified slightly from the chapter by the initial authors in the first edition of Diagnostic Cytopathology of Serous Fluids.

Evaluation of IL-2 and Dexamethasone intracavitary injection on the management of malignant effusion in children with solid tumors or lymphoma

BACKGROUND

Currently, no available coherent management protocol exists for pediatric cancers associated with pleural effusion, ascites, and pericardial effusion. This study aimed to retrospectively present our experience in treating pediatric cancer patients with pleural effusion, ascites, and pericardial effusion using interleukin-2 (IL-2) and dexamethasone (DEX) intracavitary injections.

METHODS

Between January 1st, 2008 and December 31st, 2020, medical reports of patients diagnosed with solid tumors or lymphoma were checked to identify patients diagnosed with > 2 cm pleural effusion, and/or more than grade 1 ascites, and/or more than small pericardial effusion. Patients diagnosed with effusions and treated with IL-2 and DEX were identified as being in the effusion group. Meanwhile, patients with the same primary tumors and effusions but did not receive interleukin 2 and DEX injection were reviewed and classified as the control group.

RESULTS

Forty patients with solid tumors and 66 patients with lymphoma were further diagnosed with pleural effusion, ascites, or pericardial effusion. A total of 85 patients received IL-2 and DEX injection while the remaining 21 did not. The Kaplan Meier analysis revealed a significant difference between the two groups, with p < 0.01 for event free survival (EFS) and p < 0.01 for overall survival (OS), both of which had p < 0.01. Hazard ratio was found to be 0.344 for OS and 0.352 for EFS.

CONCLUSIONS

This retrospective study illustrates that thoracic, intraperitoneal, or pericardial intracavitary injection of DEX plus IL-2 can be an effective and safe treatment for pediatric cancers with pleural effusion, ascites, and pericardial effusion.

A Review of Effusion Cytomorphology of Small Round Cell Tumors

BACKGROUND

Small round cell tumors (SRCTs) are a broad category of diverse malignant tumors composed of monotonous undifferentiated cells. Involvement of serous fluids by SRCT is rare; however, the identification of exfoliated malignant cells is a crucial component of management and has significant implications for treatment and prognosis. The most common effusion tumors with SRCT morphology include Ewing sarcoma, synovial sarcoma, rhabdomyosarcoma (RMS), small-cell neuroendocrine carcinoma (SCNC), and desmoplastic SRCT, and the cytomorphologic distinction between these tumors is challenging. The purpose of this article is to describe the morphologic features of the most common SRCT in fluids and propose helpful ancillary testing.

SUMMARY

Effusion SRCTs display similar primitive and undifferentiated morphologic features although each has subtle variations. Ewing sarcoma is a mesenchymal neoplasm and harbors characteristic translocations t(11;22) (EWSR1-FLI1) or t(21;22) (EWSR1-ERG). In fluids, Ewing sarcoma shows poorly differentiated cells of variable size with round to oval nuclei, prominent nucleoli, and scant cytoplasm. In contrast, synovial sarcoma typically involves extremities and expresses a fusion transcript in t(X;18) (SS18-SSX). This soft tissue neoplasm demonstrates uniform cells with irregular nuclear contours, characteristic nuclear folding, and scant cytoplasm. RMS is a neoplasm arising from skeletal muscle, and the alveolar subtype demonstrates a translocation in t(2;13) (PAX3-FOXO1). The malignant cells show a spectrum of small round cells and pleomorphic large cells with rhabdoid morphology. RMS cells characteristically express myogenin and MyoD1, markers of skeletal muscle differentiation. Although SCNC is not a classic SRCT, the morphology is similar. SCNC demonstrates tight clusters of malignant cells with nuclear molding and salt-and-pepper chromatin. This tumor classically has neuroendocrine differentiation and is positive for synaptophysin and chromogranin on immunohistochemistry. And last, desmoplastic SRCT typically presents as an intra-abdominal mass in young men and characteristically harbors the translocation t(11;22) (p13;q12) (EWSR1-WT1). Cytomorphologically, the tumor shows small monomorphic cells occasionally arranged as rosette-like structures.

KEY MESSAGE

The diagnosis of SRCT can be made in effusion samples and is best achieved with a combination of morphologic features, clinical history, and ancillary testing.