TRPS1 function beyond breast: A retrospective immunohistochemical study on non-breast cytology specimens.

INTRODUCTION: Trichorhinophalangeal syndrome type 1 (TRPS1) has emerged as a reliable immunohistochemistry (IHC) marker for identifying breast origin in metastatic carcinomas. This study investigates the utility of TRPS1 IHC in non-breast cytology specimens. MATERIALS AND METHODS: A retrospective search of our pathology database for the year 2021 identified fluids (pleural and peritoneal) and liver, lung and bone fine needle aspirations (FNAs) with surgical follow-up confirming non-breast metastatic carcinomas. Cell blocks from cases with sufficient neoplastic cells underwent immunostaining using a rabbit polyclonal antibody against human TRPS1. Cases lacking tumor on deeper levels after the original work-up were excluded from the study. Two pathologists independently interpreted the TRPS1 staining. RESULTS: Of 136 cases assessed, 31 (22.79%) exhibited positive TRPS1 staining, while 105 (77.21%) were nonreactive. Positivity rates were observed in tumors of Mullerian cell origin, gastrointestinal tract (GIT), and lung origin at 28.85%, 25%, and 21.57%, respectively. Of the tumors of Mullerian cell origin 10 (66.67%) were serous carcinomas, 4 (26.67%) were endometrioid carcinomas, and one (6.67%) was a clear cell carcinoma. Lung tumors comprised seven (63.64%) squamous cell carcinomas and four (36.36%) adenocarcinomas, while the gastrointestinal tumors consisted of 14 (80%) adenocarcinomas and one (20%) squamous cell carcinoma. CONCLUSIONS: Although recognized as a sensitive marker for mammary carcinomas, TRPS1 immunostaining was also detected in Mullerian, lung, and GIT carcinomas. This highlights the significance of being cautious when depending solely on TRPS1 immunostaining to distinguish metastatic breast tumors.

Utility of TRPS-1 immunohistochemistry in diagnosis of metastatic breast carcinoma in cytology specimens.

INTRODUCTION: At present, GATA binding protein 3 (GATA-3) is the most frequently used diagnostic immunohistochemical (IHC) marker for breast carcinoma (BC). However, it is not specific and has very low sensitivity for triple-negative BC (TNBC). SRY-box transcription factor 10 (SOX-10) and trichorhinophalangeal syndrome type 1 (TRPS-1) have been suggested for inclusion in the diagnostic workup of TNBC. TRPS-1 has not been established in cytology specimens as a diagnostic IHC marker for metastatic BC (MBC). Hence, in the present study we evaluated the utility of TRPS-1 in diagnosing MBC in cytology specimens. MATERIALS AND METHODS: MBC cases diagnosed on cytology specimens from January to October 2020 were included in the present study. Only cases with hormonal status available and ≥20 tumor cells on cell blocks were included in the study. The cell blocks were assessed for TRPS-1, GATA-3, and SOX-10 IHC marker positivity (intensity and percentage of tumor cells). The results were correlated with the specimen type (fine needle aspiration [FNA] versus body fluid) and various BC prognostic subgroups. RESULTS: We analyzed 61 cases, including 33 body fluid and 28 FNA (13 lymph node, 10 bone, 2 liver, 2 soft tissue, and 1 lung) specimens. TRPS-1 had 97.2% positivity in ER/PR+ (estrogen receptor/progesterone receptor-positive) MBC compared with GATA-3, which had 100% positivity in the same group. TRPS-1 showed high positivity in 35 of 37 cases (94.6%) and intermediate positivity in 1 (2.6%) and was negative/low positive in 1 case (2.7%). In contrast, GATA-3 showed high positivity for all 37 cases (100%). SOX-10 showed positivity in only 1 of 37 cases (2.7%), with intermediate positivity. In the HER2+ (human epidermal growth factor receptor 2-positive) group, TRPS-1 showed high positivity in 5 of 7 cases (71.4%), intermediate positivity in 1 case (14.3%), and negativity in 1 case (14.3%). However, GATA-3 showed high positivity in 6 of 7 cases (85.7%) and negative/low positivity in 1 case (14.3%). SOX-10 was negative in all 7 cases. In TNBC, TRPS-1 showed high positivity in 16 of 17 cases (94%) and intermediate positivity in 1 (5.9%), and GATA-3 showed high positivity in 9 (53%), intermediate positivity in 2 (11.8%), and low positive/negative in 6 of the 17 cases (35.3%). TRPS-1 expression was significantly higher than GATA-3 expression for the number of positive cases (P = 0.07), mean percentage of positive tumor cells (P = 0.005), and intensity of reactivity (P = 0.005). SOX-10 expression was present in only 5 of 17 cases (29%), with a mean percentage of positivity in the tumor cells of 26.5% and intensity of 0.8. No differences were found in the IHC results between the different specimen types (FNA versus fluid) in any group. CONCLUSIONS: TRPS-1 is a highly sensitive new diagnostic IHC marker for breast carcinoma, with a similar positivity rate in ER/PR+ and HER2+ BC compared with GATA-3 and a higher positivity rate than GATA-3 and SOX-10 in TNBC in cytology specimens. In particular, when only a few clusters of tumor cells are present on the cell block, TRPS-1 can be highly useful, because its mean percentage of positive tumor cells and intensity are higher than those of other IHC markers.

Adequacy of pleural fluid cytology for comprehensive molecular analysis of lung adenocarcinoma: Experience of a large health-care system.

Objectives: Pleural fluid evaluation is an effective modality for identifying actionable genetic mutations to guide therapy in lung carcinoma. Clinicians requesting molecular studies often send large volumes of fluid to be processed that is not possible or cost effective and is hence not standard of practice in most cytopathology laboratories. We wanted to establish the characteristics of an adequate specimen that would yield reliable results with current molecular testing platforms. Material and Methods: A review of 500 malignant pleural effusions, from pulmonary and non-pulmonary sources, was undertaken over a 4-year period. Of these 44 cases (from 42 patients) that were positive for primary lung adenocarcinoma were included in the study. Molecular analysis was performed on 42 specimens. A complete next generation sequencing (NGS) panel was performed on 36 specimens. Individual testing for estimated glomerular filtration rate, KRAS, anaplastic lymphoma kinase, and ROS1 was performed on six specimens. The number of malignant cells and proportion of tumor to non-tumor nucleated cells (T: NT) on cell blocks was recorded as <20%, 20-50% and >50%. Results: The minimum volume on which a complete NGS panel could be performed was 20 ml with cell count of 1000 and T: NT proportion of 20-50%. The minimum number of tumor cells required for successful molecular analysis for T: NT proportion of <20%, 20-50%, and >50% was 300, 250, and 170 cells, respectively. Conclusion: We concluded that tumor cell proportion, rather than specimen volume, is of prime importance for determining the efficacy of pleural fluid for molecular studies. Evaluation of both absolute and relative numbers of tumor cells is critical for assessing the adequacy and predicting successful yield for molecular analysis.

The role of cytology as an effective tool in management of omental and peritoneal lesions: Experience of a large health care system.

BACKGROUND: The aim of this study is to assess the efficacy of cytology in omental or peritoneal lesions. METHODS: A retrospective review of the pathology database for cytology cases of peritoneal or omental nodules over a 3-year period (2016-2018) was conducted. The cases consisted of either FNA only (FO); FNA and Core biopsy (FCB) or Touch prep and core biopsy (TCB). Cases were further divided based on the prior history of carcinoma. Concordance rates of cytologic diagnosis with histologic diagnosis were studied. RESULTS: Out of 104 cytology cases reviewed, 60 (57.7%) had prior history of cancer (PHC) and 44 (42.3%) had no prior history of cancer (NPHC). Of the cases with PHC, 43(71.66%) were recurrence, 10 (16.66%) were second cancer, and 7 (11.66%) were non-neoplastic lesions. Of the cases with NPHC, 38 (86.4%) had a second cancer diagnosis, while 6 (13.6%) were non-neoplastic. For FO only cases, 11 of 35 (31.4%) had follow up and 9 of 11 (81.8%) were concordant. For FCB cases, 6 out of 39 (15.4%) had follow up and 6 (100%) were concordant. For TCB cases, 9 out of 30 (30%) had follow up and 9 (100%) were concordant. A definite diagnosis was reached in 30/35, 39/39, and 29/30 cases in FO, FCB, and TCB, respectively. CONCLUSION: In summary, cytologic evaluation of omental lesions is an effective tool in providing accurate diagnosis and guiding further management. Also, the results based on our study show that the combined techniques are superior at reaching a definitive diagnosis.