TRPS1 outperforms GATA3 in pleural effusions with metastatic breast carcinoma versus mesothelioma.

INTRODUCTION: In evaluating malignant pleural fluid cytology, metastatic adenocarcinomas and mesotheliomas are often differential diagnoses. GATA binding protein 3 (GATA3) has historically been used to confirm metastatic breast carcinomas; however, GATA3 has low specificity if mesothelioma is included in differential diagnoses. Trichorhinophalangeal syndrome type 1 (TRPS1) protein is expressed in all types of breast carcinomas, with reported high specificity and sensitivity. We investigated the performance of TRPS1 immunohistochemistry (IHC) and compared it to GATA3 in pleural fluids diagnosed with metastatic breast carcinoma and mesothelioma. METHODS: Thirty-six consecutive ThinPrep pleural fluids and 4 pleural fine needle aspirations (FNAs) with diagnoses of metastatic breast carcinoma (21) and mesothelioma (19) were retrieved, and IHC with TRPS1 and GATA3 was performed on all. Immunoreactivity scores for TRPS1 were calculated by multiplying percentage of immunoreactive cells by staining intensity. Immunoreactivity scores were negative if 0 or 1, low positive if 2, intermediate positive if 3 or 4, or high positive if 6 or 9. Nuclear immunoreactivity of ≥10% with at least moderate intensity was judged GATA3 positive. RESULTS: GATA3 showed immunoreactivity in all metastatic breast carcinomas and 84% of mesotheliomas. TRPS1 was immunoreactive in all breast carcinoma cases (18 with a score of 9 and 3 with a score of 6). TRPS1 showed low positivity in 5% of mesothelioma cases with all other cases being negative. CONCLUSION: When cytomorphologic differential diagnoses of mesothelioma exist, TRPS1 is a more specific marker than GATA3 for confirmation of metastatic breast carcinoma in pleural fluid cytology.

Malignant rhabdoid tumor: Cyto-histologic correlation and immunohistochemical characterization of a rare pediatric malignancy and its differential diagnoses.

Malignant rhabdoid tumor of the kidney (MRTK) is a rare aggressive pediatric renal tumor which can be diagnosed via fine-needle aspiration (FNA) cytology and core biopsy. The diagnosis of MRTK is challenging, and requires morphologic, immunohistochemical and clinical correlation to distinguish it from other entities. The differential diagnosis includes Wilms tumor, desmoplastic small round cell tumor, rhabdomyosarcoma, synovial sarcoma, renal medullary carcinoma, and epithelioid sarcoma. Here we describe a case of MRTK diagnosed on renal cytology and core biopsy with immunohistochemistry and follow by nephrectomy with gross and morphologic findings.

Desmoid fibromatosis involving the pancreas: A retrospective case series with clinical, cytopathologic and radiologic correlation.

Desmoid-type fibromatosis (desmoid tumors) which involve the pancreas is an infrequent diagnosis which clinically can mimic both neoplastic and non-neoplastic lesions of the pancreas. The cytologic features of loosely cohesive cytologically bland (myo)fibroblastic cells are non-specific, however the long fascicular growth pattern and the presence of ß-catenin mutation with positive nuclear immunohistochemical staining or molecular testing allows for definitive diagnosis. While many previously reported desmoid tumors of the pancreas have been surgically resected, conservative management with a "watch and wait" approach is also an effective mode of management for these tumors. Herein, we report the largest case series of pancreatic desmoid tumors with clinical, cytopathologic, and radiologic correlation.

Cyto-histologic correlation of crystal-storing histiocytosis: Rare presentation in breast, predating diagnosis of B-cell lymphoma by two years.

Crystal-storing histiocytosis (CSH) is a rare disorder characterized by the accumulation of crystalized immunoglobulins within the cytoplasm of histiocytes. It is often associated with an underlying lymphoproliferative or plasma cell disorder. Most patients with CSH are asymptomatic in regard to the disease and are incidentally discovered. Herein we present cyto-histologic correlation of a rare example of CSH presenting with a two-year interval between original diagnosis of CSH and confirmation of a low-grade B-cell lymphoma.

The Stapes in Otosclerosis: Osteoarthritis of an Ear Ossicle.

Otosclerosis is a pagetoid proliferation of bone remodeling, vascular proliferation, bone resorption and new bone formation in the tympanic region of the temporal bone. The resulting anklyosis of the stapes footplate as it articulates with the oval window is the most common cause of conductive hearing loss in young to middle aged, predominantly Caucasian individuals. The characteristic histologic features have been well documented by autopsy studies of the temporal bone. Although stapedectomy is the surgical treatment for otosclerosis, the stapes specimen may be submitted for gross examination only or not examined at all. A retrospective study of 73 stapedectomy specimens (2008-2019) not including the stapes footplate. Clinical features from the electronic medical record as well as standard histologic sections from surgical specimens were reviewed. Neither the stapedal head nor crura showed histologic features of otosclerosis. There was mild osteoarthritis affecting the head, possibly as a consequence of persistent ossicular vibration superimposed on the ankylosed rigidity. The most common changes were surface fissuring (65%), cartilaginous erosion (49%) and irregularity of the osteochondral interface (51%). An occasional osteophyte (8%) was observed. The ear ossicles, embryologically analogous to long bones of the extremities, develop via endochondral ossification and exhibit articular surfaces of hyaline cartilage. The present observations suggest that a consequence of otosclerotic ankylosis is osteoarthritis of the stapedal head. In this study, the histological features could not be correlated with the severity of hearing loss or duration of clinical disease.