Cytologic Features of Inflammatory Rhabdomyoblastic Tumor Using Conventional and Liquid-Based Cytology Preparations: A Case Report.
Yohei Yamaguchi, Toru Odate, Keito Ogino et al.
✦ AI-curated · Sources linked
Case in brief
A man in his 60s with pharyngeal discomfort was diagnosed with tonsillar diffuse large B-cell lymphoma. Staging PET-CT also showed focal uptake in the left tibialis anterior muscle, initially raising concern for lymphoma involvement. Ultrasound-guided biopsy suggested inflammatory rhabdomyoblastic tumor (IRMT), confirmed after resection. Cytology showed atypical cells with enlarged, variably shaped nuclei and abundant cytoplasm amid reactive lymphocytes and histiocytes; the atypical cells expressed desmin and MyoD1. After resection, he received R-CHOP for lymphoma. At follow-up less than 6 months after resection, there was no evidence of IRMT recurrence or metastasis.
What made this case unusual
The report details IRMT cytology across imprint, crush, and liquid-based preparations, showing a biphasic pattern of atypical rhabdomyoblastic cells in a lymphocyte- and histiocyte-rich background. Cross-striations were absent, making immunocytochemical confirmation of rhabdomyoblastic differentiation useful.
Diagnostic / clinical pearl
In a lymphocyte- and histiocyte-rich specimen, atypical cells with rhabdomyoblastic features should prompt consideration of IRMT; desmin and MyoD1 positivity can support that differentiation.