Characteristics of Metastatic and Nonmetastatic Pulmonary Sclerosing Pneumocytomas: A Clinicopathological Study of 68 Cases and 15 Reported Metastatic Cases.

To characterize the clinicopathologic features of pulmonary sclerosing pneumocytoma (PSP) and compare these features between the tumors with and without metastasis, 68 cases of PSP (1/68 [1.47%] with metastasis) diagnosed from 2009-2022 in our hospital and 15 previously reported metastasizing cases were studied. There were 54 female patients and 14 male patients, with age ranging from 17 to 72 years and tumor size ranging from 0.1 to 5.5 cm (mean, 1.75 cm). In all, 85.4% of the cases presented with ≥2 patterns, including papillary, sclerotic, solid, and hemorrhagic. Thyroid transcription factor 1, epithelial membrane antigen, CKpan, and CK7 were expressed in surface cells in 100% of the cases and napsin A was expressed in 90% of the cases. Stromal cell expression of these markers occurred in 100%, 93.9%, 13.5%, 13.8%, and 0% of the cases, respectively. Of the 16 PSP cases with metastasis, 8 were female patients and 7 were male patients, with age ranging from 14 to 73 years. The tumor size ranged from 2.5 to 12 cm (mean, 4.85 cm). Forty-five of the cases were negative for BRAF V600E immunostaining and 6 were focally weak positive, in which fluorescent PCR tests showed no detectable mutations. There were significant differences in gender, age, and tumor size between PSP cases with and without metastasis. No BRAF V600E mutation was found in patients with PSP. AKT1 p.E17K mutations were detected in both the primary lung tumor and the lymph node metastatic tumor of our PSP case with lymph node metastasis. In conclusion, PSP is an uncommon pulmonary neoplasm with significant female predilection and has distinct morphologic and immunohistochemical characteristics. The BRAFV600E mutation was not detectable in patients with PSP and thus may not involve in its tumorigenesis. Most PSP tumors are benign, with a minority exhibiting potential for metastasis and malignant behavior.

Application of TFE3 Immunophenotypic and TFE3 mRNA Expressions in Diagnosis and Prognostication of Adrenal Cortical Neoplasms and Distinction From Kidney Tumors.

We explored the application of TFE3 immunostaining and TFE3 mRNA expression in the differential diagnosis and prognostication of adrenal cortical tumors and distinction of the latter from clear cell renal cell carcinoma (ccRCC) which show significant morphologic overlap. TFE3 immunostaining was performed on a large cohort of samples including 40 adrenal cortex tissues, 95 adrenocortical adenoma (ACA), 11 adrenocortical carcinoma (ACC), 53 ccRCC, and 18 pheochromocytomas. TFE3 was compared with other immunomarkers melan-A, inhibin-α, synaptophysin, chromogranin A, CAIX and CD10. One hundred percent normal adrenal cortices and 94% ACA were strongly and diffusely stained for TFE3 while no ACC showed diffuse staining. TFE3 is thus useful in distinguishing ACA from ACC. TFE3 is also useful in separating ACC from ccRCC as 64% ACC showed partial, while only 7% of ccRCC showed partial TFE3 staining. Only 1 pheochromocytoma showed focal weak TFE3 staining. Results also demonstrated superiority of TFE3 over other commonly used immunomarkers. TFE3 gene rearrangement testing by fluorescence in situ hybridization showed no rearrangement in 6 TFE3 positive adrenal tumors. TFE3 mRNA were analyzed by the Cancer Genome Atlas database and we found TFE3 mRNA expression correlated with overall patient survival in ACC. Our study showed usefulness of TFE3 in distinguishing ACA from ACC, and ACC from ccRCC. TFE3 is superior over other commonly used immunomarkers for adrenal tumors. In addition, decreased TFE3 immunoexpression and TFE3 mRNA expression may carry poor prognostic implication in adrenal tumors.

A comparative study of Kimura's disease and IgG4-related disease: similarities, differences and overlapping features.

AIMS: To compare the fibroinflammatory diseases Kimura's disease (KD) and immunoglobulin (Ig)G4-related disease (IgG4RD) and to explore their possible relationship. METHODS AND RESULTS: Forty-six cases of KD and 29 IgG4RD from our institution diagnosed from 2011 to 2020 were studied. They were compared with each other on clinical, pathological and immunohistological features. There were similar clinical features, except that IgG4RD affected an older patient population, with more frequent salivary gland involvement and KD affected head and neck lymph nodes, and showed blood eosinophilia more frequently than IgG4RD. IgG4RD exhibited frequent storiform fibrosis and obliterative phlebitis, while KD showed more frequent tissue eosinophilia, eosinophilic abscess, germinal centre eosinophilic deposit and vascularisation. Twenty to 30% of KD had more than 50 IgG4+ plasma cells (PC) per high-power field (HPF) and IgG4/IgG+ PC ratio exceeding 40%. These parameters, however, occurred in 100% of IgG4RD. Significantly more KD had >10 IgE+ PC/HPF and lymphoid germinal centre IgE reticular staining compared to IgG4RD. All these histological and immunohistological features are overlapping in the two diseases, although they differed with statistical significance. CONCLUSION: Our study confirmed that there is significant overlap in clinical, pathological and immunohistological features between KD and IgG4RD. It is important to recognise these overlapping features, and correlation with a clinicopathological picture is required in differential diagnoses. The overlapping features also suggest a possible close relationship between KD and IgG4RD, which could represent different facets of a continuous fibroinflammatory disease spectrum.

An unusual case report of indolent T-cell lymphoproliferative disorder with aberrant CD20 expression involving the gastrointestinal tract and bone marrow.

BACKGROUND: Indolent T-cell proliferative disorder of the GIT is a rare and provisional entity in the revised WHO 2016 classification. The patients usually have prolonged survival with persistent disease even without any treatment. CASE PRESENTATION: The 46 years old male patient has been followed up for more than 6 years without chemotherapy. Repeated gastrointestinal biopsies showed expansion of the lamina propria extending to the submucosa by small to medium sized lymphocytes with minimal cytologic atypia. The lymphoid cells were positive for CD3, CD43, TIA-1, CD2, CD7 and the B-cell marker CD20; but negative for CD4, CD8, PAX5, CD56, cyclinD1, granzyme (GraB) and Epstein Barr virus-encoded RNA (EBER). Ki-67(MIB1) index was less than 10%. Molecular tests demonstrated a clonal rearrangement for T-cell receptor γ (TCR γ) gene but immunoglobulin chain (IgH, IgK, IgL) gene remained germline. Recognition of possible aberrant CD20 expression in indolent T-cell LPD is important to avoid potential diagnostic pitfall and improper treatment. CONCLUSIONS: We present an unusual case of indolent T-cell lymphoproliferative disorder with aberrant CD20 expression, Recognition of this unusual immunophenotype of indolent T-cell LPD of GI helps to eschew misdiagnosis of B-cell and other high grade lymphomas and inappropriate aggressive treatment.

Primary pericardial primitive neuroectodermal tumor: a case report and review of literature.

Primitive neuroectodermal tumor (PNET) is a rare, high-grade malignant tumor that most commonly occurs in the peripheral nervous system, bone, and deep soft tissues. It is extremely rare in the pericardium. To the best of our knowledge, only two patients with primary PNET of the pericardium have been reported so far in the literature. We report a case of PNET of the pericardium in a 13-year-old female patient, who was referred to our hospital for dyspnea and edema of lower extremities. Computer tomography (CT) scanning revealed a soft tissue mass in the pericardium which was surgically removed. The diagnosis of PNET was confirmed by histology, immunohistochemistry and molecular study. The patient was alive and well at follow up 8 months after surgery.