Schwannomas are benign, slow-growing peripheral nerve sheath tumors commonly occurring in the head, neck, and flexor regions of the extremities. Although most schwannomas are easily diagnosable, their variable morphology can occasionally create difficulty in diagnosis. Reporting pathologists should be aware that schwannomas can exhibit a broad spectrum of morphological patterns. Clinical and radiological examinations can show correlation and should be performed, in conjunction with ancillary tests, when appropriate. Furthermore, deferring a definitive diagnosis until excision may be necessary for small biopsy specimens and frozen sections. This report underscores these challenges through examination of two unique schwannoma cases, one predominantly cellular and the other myxoid, both of which posed significant challenges in histological interpretation.
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Plexiform Schwannoma Over the Anterior Chest Wall: A Clinicopathological Review Debojyoti Sasmal, Saswata Barenya, Hinglaj Saha, Pankaj Kumar Halder Amrita Journal of Medicine.2025; 21(2): 95. CrossRef
Background The cytologic diagnosis of poorly differentiated thyroid carcinoma (PDTC) is difficult because it lacks salient cytologic findings and shares cytologic features with more commonly encountered neoplasms. Due to diverse cytologic findings and paucicellularity of PDTC, standardization of cytologic diagnostic criteria is limited. The purpose of this study is to investigate and recognize diverse thyroid findings of fine needle aspiration (FNA) cytology and frozen smear cytology in diagnosis of this rare but aggressive carcinoma.
Methods The present study included six cases of FNA cytology and frozen smears of histologically diagnosed PDTCs.
Results PDTC showed cytologic overlap with well-differentiated thyroid carcinomas (WDTCs). Five of six cases showed dedifferentiation arising from well differentiated thyroid carcinomas. Only one de novo PDTC showed highly cellular smears composed of discohesive small cells, high nuclear/cytoplasmic (N/C) ratio, prominent micronucleoli, and irregular nuclei. Retrospectively reviewed, these findings are highly suspicious for PDTC. Cytologic findings of nuclear atypia, pleomorphism, and irregularity were frequently found, whereas scattered small cells were seen only in the de novo case.
Conclusions Heterogeneous cytologic findings of PDTCs are shared with those of WDTCs and contribute to difficult preoperative cytologic diagnoses. Most PDTCs show dedifferentiation from WDTCs. Albeit rare, de novo PDTC should be considered with cytology showing discohesive small cells with high N/C ratio. This will enable precise diagnosis and prompt treatment of this aggressive malignancy
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An Unexpected Finding of Poorly Differentiated Thyroid Carcinoma in a Toxic Thyroid Nodule Kimberly Yuang, Huda Al-Bahadili, Alan Chang JCEM Case Reports.2023;[Epub] CrossRef
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Myunghee Kang, Dong Hae Chung, Na Rae Kim, Hyun Yee Cho, Seung Yeon Ha, Sangho Lee, Jungsuk An, Jae Yeon Seok, Gie-Taek Yie, Chan Jong Yoo, Sang Gu Lee, Eun Young Kim, Woo Kyung Kim, Seong Son, Sun Jin Sym, Dong Bok Shin, Hee Young Hwang, Eung Yeop Kim, Kyu Chan Lee
J Pathol Transl Med. 2019;53(2):104-111. Published online January 14, 2019
Background Pathologic diagnosis of central nervous system (CNS) neoplasms is made by comparing light microscopic, immunohistochemical, and molecular cytogenetic findings with clinicoradiologic observations. Intraoperative frozen cytology smears can improve the diagnostic accuracy for CNS neoplasms. Here, we evaluate the diagnostic value of cytology in frozen diagnoses of CNS neoplasms.
Methods Cases were selected from patients undergoing both frozen cytology and frozen sections. Diagnostic accuracy was evaluated.
Results Four hundred and fifty-four cases were included in this retrospective single-center review study covering a span of 10 years. Five discrepant cases (1.1%) were found after excluding 53 deferred cases (31 cases of tentative diagnosis, 22 cases of inadequate frozen sampling). A total of 346 cases of complete concordance and 50 cases of partial concordance were classified as not discordant cases in the present study. Diagnostic accuracy of intraoperative frozen diagnosis was 87.2%, and the accuracy was 98.8% after excluding deferred cases. Discrepancies between frozen and permanent diagnoses (n = 5, 1.1%) were found in cases of nonrepresentative sampling (n = 2) and misinterpretation (n = 3). High concordance was observed more frequently in meningeal tumors (97/98, 99%), metastatic brain tumors (51/52, 98.1%), pituitary adenomas (86/89, 96.6%), schwannomas (45/47, 95.8%), high-grade astrocytic tumors (47/58, 81%), low grade astrocytic tumors (10/13, 76.9%), non-neoplastic lesions (23/36, 63.9%), in decreasing frequency.
Conclusions Using intraoperative cytology and frozen sections of CNS tumors is a highly accurate diagnostic ancillary method, providing subtyping of CNS neoplasms, especially in frequently encountered entities.
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BACKGROUND Core needle biopsy (CNB) is widely used as the initial sampling method for breast cancer. And because frozen section (FS) diagnosis is rapid and reliable, we studied the diagnostic agreement between the diagnosis of FS of CNB and final diagnosis after surgery to evaluate the diagnostic accuracy of the FS of CNB. METHODS Of 409 patients who were preoperatively diagnosed by FS of CNB and who underwent final surgery from 1996 through 2000, 24 cases were found to be ductal carcinoma in situ (DCIS) and 385 cases invasive carcinoma (IC). The diagnoses of FS of CNB were compared with final diagnoses. RESULTS The diagnostic accuracy of carcinoma is 63.6% for DCIS and 86.9% for invasive carcinoma. Five cases (1.2%) could not be diagnosed because of material insufficiency for diagnosis. Twenty two cases (5.4%) were diagnosed as benign on FS, among which 20 (90.9%) were misdiagnosed by sampling error. Twenty seven cases (6.7%) were deferred on FS, 4 of these cases were DCIS, 5 were invasive lobular carcinoma (ILC), the rest displayed low nuclear grades or marked freezing artifacts. CONCLUSIONS The diagnostic accuracy of FS of CNB is very high except for cases of ILC and low grade DCIS. Considering the advantage of rapid evaluation, more definitive diagnosis, familiarity by pathologists and availability of ancillary study, FS of CNB is very useful method as the preoperative evaluation.