OFP-20-010 Primary renal synovial sarcoma: A clinicopathologic, immunohistochemical and molecular genetic study of 16 cases J. Schoolmeester * , J. Cheville, A. Folpe * Mayo Clinic, Dept. of Anatomic Pathology, Rochester, MN, USA Objective: Primary renal synovial sarcoma (R-SS) is a rare malignant neoplasm. Approximately 45 cases have been described, chiefly as case reports or as part of relatively limited small studies. We studied the clinicopathological, immunohistochemical (IHC) and molecular genetic features of 16 well-characterized R-SS. Method: All available slides for 16 institutional and consultation cases of R-SS were reviewed. An IHC panel (TLE1, BCL2, cytokeratins, S100, CD34, INI1) was performed. RT-PCR for SS18-SSX1/2 or FISH for SS18 rearrangement was performed. Follow-up was obtained. Results: The patients (9 M, 7 F) ranged from 17 to 78 years (mean 46). All tumors were of monophasic fibrous type. IHC results: all cases were strongly positive for TLE1 and BCL2; focally positive or negative for cytokeratins; negative for S100 and CD34; and showed retained INI1 expression. Molecular genetic results were: SS18-SSX1 (5 cases), SS18-SSX2 (10 cases), SYT rearrangement (1 case). Follow-up (5 cases): 3 dead of disease, 2 alive without disease. Conclusion: Our data show a striking overrepresentation of the SS18-SSX2 fusion subtype among R-SS, in contrast to other SS, in which the SS18-SSX1 fusion subtype accounts for two-thirds of cases. The reasons for this difference are unclear. The prognosis for R-SS appears similar to that of SS of more common locations. Objective: New data related to the diagnosis and therapy of lung cancer have also affected the position of the pathologist in this area. Principal changes in its classification have appeared in relation to adenocarcinoma and partly also in the large cell type of lung cancer. Method: Presented data represent a five-year retrospective study of a series of 546 cases of lung cancers analyzed in our Institute. Besides routine HE staining the following immunohistochemical reactions were used: antibody against TTF-1, Surfactant A, Chromogranin, Synaptophysin, CK7, AE1/AE3, p63, 34βE12, CD56 and Napsin A. Results: Using the WHO, 2004 Classification of Lung Cancer, an unusual phenomenon of the return of squamous cell cancer (SCC) prevalence over adenocarcinoma has been documented, which in the earlier years has equated the SCC. The difference in obtaining the tissue samples, and changes in the geographical origin of certain patients of Eastern Slovakia may partly explain these differences. Though the new Travis classification (J Thorac Oncol, 2011) was not used, there prevailed mixed forms also in our series. Conclusion: It is important to respect new information regarding the Classification of Lung Cancer, especially in the category of adenocarcinoma. The constructive collaboration of pathologists with clinicians is recommended. Objective: Extranodal marginal zone lymphoma MALT lymphoma and carcinoid are neoplasms occurring most frequently in the gastrointestinal tract and respiratory system. Although each of them occurs relatively frequently and separately, the simultaneous appearance of these two neoplasms is exceptionally rare. Method: We report an exceptional synchronous association of MALT lymphoma and typical carcinoid in the lung. Results: A 52-year-old male with Sjögren's syndrome presented with cough and chest pain with no improvement after antibiotherapy. Bronchial fibroscopy was normal. Computed tomography showed a diffuse interstitial pneumopathy with a persistent left lower lobe nodule suspected of malignancy. A surgical resection of the nodule was achieved. Histopathologically, it measuring 1.2 cm in diameter and was composed of association of malt lymphoma and typical carcinoid tumor which were focally admixed. Immunohistochemical stains were strongly reactive to endocrine marker in carcinomatous component. Tumor cells were diffusely CD20 positive in lymphomatous component. Assessment of extent of lymphoma revealed a gastric location. The patient received chemoptherapy. He's still alive since 8 months. Conclusion: The best of our knowledge, this is the first report of such a collision lung tumor at the same anatomical site. The aim of this study is to describe the pathogenesis and clincicopathological feartures of such exceptional association. Objective: Primary mucoepidermoid carcinoma is rare comprise less than 1 % of all lung tumors. It is characterized by the presence of squamoid cells, mucin-secreting cells and intermediate type. On the basis of morphological and cytological features, it is divided into low and highgrade types. Method: We report a retrospective study of 15 cases diagnosed during a 15-year period. Diagnosis was made by histological examination of specimen obtained from lobectomy in 13 cases and pneumonectomy in 2 cases. No patient had history of salivary mucoepidermoid carcinoma. Results: There were 13 men and 2 women ranging in age from 10 to 76 years. Computed tomography showed a well circumscribed tumor arising in bronchus in all cases. A bronchial fibroscopy showed a main, lobar or segmental mass. Bronchial biopsy revealed a non-small-cell carcinoma in only one case. Histologically, tumors were classified into 7 low grade mucoepidermoid carcinoma and 8 high grade mucoepidermoid carcinoma. Patients with low grade carcinoma remain alive after surgery alone. Patients with high grade carcinoma received chemotherapy, four of them developed distance metastasis. Conclusion: Mucoepidermoid carcinoma is a rare primary malignancy of the tracheobronchial tree which is difficult to diagnose by limited biopsy. The prognosis is variable and depends upon the histological grade. Objective: Primary pulmonary MALT lymphoma is considered to originate from MALT of the bronchus secondary to autoimmune or inflammatory processes. Although, it comprises more than two-thirds of all primary non-Hodgkin's lymphoma of the lungs, it is a rare entity and accounts for less than 1 % of all lymphomas. Method: We report a retrospective study of 6 cases of Malt pulmonary lymphomas diagnosed during an 8-year period. Diagnosis was made on surgical pulmonary biopsy in 2 cases, bronchial biopsy in 3 other cases and on lobectomy in one case. Results: There were 4 women and 2 men ranging in age from 48 to 74 years. Two patients had a history of Sjoren's syndrome and one had a history of previous mammary carcinoma. Computed tomography revealed bilateral nodules in 3 patients, lung mass in 2 patients and an area of consolidation in one patient. Fiberoptic bronchoscopy showed bronchial stenosis in only 3 cases. Morphologically, the neoplasms had features typical of MALT lymphoma. One patient was treated with surgery alone and 5 received chemotherapy. Five patients remained alive while one patient presented with recurrence. Conclusion: Pulmonary MALT lymphomas are characterized by an important dissociation between clinical expression and radiological pattern. Therefore, histological documentation is mandatory to ensure diagnosis. Objective: Malignant mesothelioma (MM) is an aggressive tumour with a poor prognosis. Carbonic anhydrases and their inhibitors offer an opportunity for developing novel anticancer drugs, as well as diagnostic and prognostic tools. Carbonic anhydrase IX (CAIX) is a membranous metalloenzyme involved in cell adhesion and pH homeostasis. It is a direct target of hypoxia-inducible factor and serves as a marker of hypoxia. This study was designed to assess systematically CAIX expression in MM of pleura and peritoneum, and their benign counterparts. Method: 47 MMs of pleura (41 epithelioid, 1 biphasic, 2 sarcomatoid) and peritoneum (3 epithelioid), and 14 normal or reactive pleural samples were analyzed. CAIX expression was determined using immunohistochemistry. Membranous immunoreactivity was evaluated semiquantitatively. Specimens were divided into five subgroups according to the staining pattern and intensity. Results: 95,7 % (45/47) of MMs expressed CAIX. All epithelioid mesotheliomas showed at least a weak focal (8,5 %, 4/47), but predominantly a strong diffuse (70,2 %, 33/47) staining with CAIX antibody, without any perinecrotic pattern. Sarcomatoid mesotheliomas were negative. Normal mesothelial cells were diffusely positive. Conclusion: These data suggest that mechanisms of CAIX overexpression in MM are different than due to hypoxia and appear promising in prospective use of specific therapeutic CAIX targeting in advanced mesothelioma. Objective: EML4-ALK crizotinib therapy needs validation at lower cost and rapid answer in Pathology routine. Method: Histological/WHO 2004 and CK7, TTF1, CK5.6, CD56/chromogranin and vimentin panel classifications with ALK (clone 5A4, Novocastra Laboratories Ltd, Newcastle, United Kingdom) were applied to paraffin sections of 35 bronchial-pulmonary carcinomas: 20 adenocarcinomas, 6 epidermoid carcinomas, 4 pleomorphic carcinomas (mixed type adenocarcinomas with large/giant/fusiform cells), 4 neuroendocrine carcinomas (NEC) (1 combined large cell NEC with adenocarcinoma and 2 with epidermoid carcinomas; 1 SCLC chromogranin positive combined with adenocarcinoma) and 1 adenosquamous carcinoma. Results: The applied antibodies specified bronchial pulmonary carcinomas subtypes clearly. In 3 over 60 years old nonsmoking females mixed type adenocarcinomas ALK expression was over 50 %: acinar, solid, micropapillary and microacinar patterns; one glandular mucinous pattern (mucinous BA pattern) and one BA pattern, all expressing TTF-1. Conclusion: In this study, 3/20 adenocarcinomas of older women had ALK protein expression, only one with a mucinous pattern. As protein positivity cases comprise a lower number, FISH described by S. Lantuejoul seems to be the most appropriate method. It is now necessary to decide whether KRAS and EGFR mutations have to be determined together and/or select TTF-1 positive adenocarcinomas (from terminal respiratory unit) raised by this approach. Objective: