[1778] Combination Analysis of Electron Microscopy and Cytology in Tumor Diagnosis

A Liu, M Hosone, S Maeda, K Azuma, H Katayama, Z Naito, M Ghazizadeh. Nippon Medical School, Tokyo, Japan

Background: At present, cytological diagnoses of tumors combined with ancillary techniques can be as precise as those of surgical pathology. The cytopathologists are challenged to make a definitive diagnosis on the basis of the cytological samples with increasing frequency. In our cytology practice, electron microscopy (EM) is routinely employed for difficult cases of tumors. We here present 6 such cases.
Design: The fine-needle aspiration cytology (FNAC) and body fluid cytology (BFC) samples were examined by routine cytology, immunocytochemistry (ICC) and EM. ICC was performed on cell block or cell-transferred cytology specimens. EM samples were prepared from cell blocks or imprint-cytology specimens obtained from cut surface of the fresh tumor tissue.
Results: Case 1: Amelanotic melanoma. FNAC showed a large pleomorphic cell tumor. HMB-45 was focally positive by ICC. By EM, premelanosomes were identified. Case 2: Primary adrenal cortical carcinoma. FNAC showed a granulomatous lesion with some large atypical cells suggesting the primary diagnosis of inflammatory pseudotumor of the liver. EM confirmed that the large atypical cells had the characteristics of adrenal cortical epithelial cells. Case 3: Peritoneal malignant mesothelioma (MM). Peritoneal BFC was Class IVV (MM, susp). By ICC and EM examinations, the diagnosis of epithelioid MM was definitive. Case 4: Metastatic adenocarcinoma of the colon. Pleural BFC was Class V (adenocarcinoma of unknown primary; lung? or colon?). ICC showed CK20(+) / CK7(-) and Villin(+). EM indicated the tumor with features of colon origin. Case 5: Pheochromocytoma. EM from imprint-cytology specimens demonstrated numerous epinephrine producing granules in the tumor cells. Case. 6: Uterine leiomyosarcoma. Routine endometrial cytology revealed a pleomorphic tumor suspicious of sarcoma. EM from imprint-cytology specimens demonstrated the features of smooth muscle differentiation.
Conclusions: The combination analysis of EM and cytology in tumor diagnosis is often powerful to help solve diagnostic dilemmas of challenging cases.
Category: Ultrastructural

Monday, March 9, 2009 1:00 PM

Poster Session II # 246, Monday Afternoon