Fine Needle Aspiration Cytology of Mammary analogue secretory carcinoma of salivary gland with t(12;15)(q13;q25) ETV6-NRTK3 translocation, initially diagnosed as acinic cell carcinoma - A CASE REPORT Department of Pathology Seoul National University College of Medicine, Seoul, Korea Ye-Young Rhee, Jaekyung Won, Minjee Park, Gaemoon Gwak, Yul Ri Chung, Eunhyang Park, In Ae Park Clinical history • A 40-year old female with a persistently recurrent salivary gland tumor (acinic cell carcinoma), as briefly mentioned below – a right partial parotidectomy 17 years ago – a right total parotidectomy and radiation therapy 8 years ago – re-excision due to locally recurred mass every year until 2 years ago Clinical history • One year ago, the follow up MRI (Magnetic Resonance Image) and PET (Positron Emission Tomography) showed newly appeared multiple enhancing lesions in the right pre-mandibular, right neck level II, IV, V and right supraclavicular area. A B Figure 1. Magnetic resonance image (MRI) and Sonogram. A. MRI showed multiple enhancing lesions including premandibular, right neck level IV, V. B. Sonogram showed enlarged LN at right supraclavicular area. Fine needle aspiration • Fine needle aspiration of these multiple enhancing lesions revealed numerous atypical epithelial cells with intracytoplasmic vacuoles, forming small acinar-like structure and papillary pattern. A B Figure 2. Fine needle aspirate of supraclavicular LN. Papanicolaou-stained slide showed (A) acinar-like structure (X 100) and (B) papillary pattern (X 200) Fine needle aspiration • Numerous atypical epithelial cells with intracytoplasmic vacuoles made us to suspect the possibility of metastasis of mammary analogue secretory carcinoma instead of acinic cell carcinoma. Figure 3. Fine needle aspirate of supraclavicular LN. Papanicolaou-stained slide showed numerous atypical epithelial cells with intracytoplasmic vacuoles. (X 400). FISH analysis • We performed FISH analysis on both surgically excised recurred mass and aspirated lymph node, and identified ETV6 rearrangement in both specimens. Figure 4. Fluorescence in situ hybridization analysis of ETV6 gene. FISH analysis on both surgically excised recurred mass and aspirated lymph node identified t(12;15)(q13;q25) ETV6-NRTK3 translocation in both specimens. Diagnosis • We initially diagnosed this aspiration case as metastatic acinic cell carcinoma, however variable sized numerous intracytoplasmic vacuoles made us to suspect the possibility of mammary analogue secretory carcinoma. • FISH analysis showing t(12;15)(q13;q25) ETV6-NRTK3 translocation proved this case was metastasis of mammary analogue secretory carcinoma. Discussion • Mammary analogue secretory carcinoma, a rare salivary gland tumor having t(12;15)(q13;q25) ETV6-NRTK3 translocation, is often misdiagnosed as other carcinomas such as acinic cell carcinoma. • Cytologic differential diagnosis point from acinic cell carcinoma - prominent extracellular and intracellular mucin - size variation of intracytoplasmic vacuole - t(12;15)(q13;q25) ETV6-NRTK3 translocation Conclusion • This case has emphasized the need for careful examination of histopathology and cytopathology, and suspicion of the mammary analogue secretory carcinoma, when we diagnose salivary gland with cytologic feature resembling acinic cell carcinoma.