Metastatic epithelioid trophoblastic tumor in retroperitoneal nodes in a case of regressed germ cell tumor of testis: An extremely rare occurrence.

Epithelioid trophoblastic tumor is an extremely rare tumor which occurs in women of the reproductive age group following a previous gestation. Its occurrence in male patients is remarkably rare, with only six cases reported in the English literature. Herein, we discuss the unusual occurrence of this tumor in a 31-years-old male patient as a component of non-seminomatous germ cell tumor. It presented as retroperitoneal metastasis with associated testicular microlithiasis (regressed germ cell tumor).

Eosinophilic solid cystic renal cell carcinoma: A series of 3 cases elucidating the spectrum of morphological and clinical features of an emerging new entity.

Eosinophilic solid cystic renal cell carcinoma (ESC-RCC) is a recently described entity, which demonstrates distinct clinical, pathological and molecular features. We present a series of three cases, the first to be reported from the Indian subcontinent. All three patients were over 50 years of age; and presented with a large kidney mass. One patient had a locally advanced disease while the other two presented with metastases. Microscopic examination revealed a tumor displaying solid-cystic and/or papillary areas composed of clear as well as eosinophilic cells in all three cases. On immunohistochemistry, all the three cases showed a unique CK20+/α-methyl-acyl-CoA-racemase + immunophenotype. Melan-A was focally positive in Case 2. Cytokeratin 7 was focally but strongly positive in Case 3. The two patients with metastatic disease were diagnosed on core biopsies and were advised oral tyrosine kinase inhibitor therapy. The third patient underwent upfront radical nephrectomy. Due to its peculiar morphology and immunoprofile, the diagnosis of ESC-RCC can be confidently made even on a core biopsy. Most cases reported till date had an indolent course. The metastatic presentation in two of our patients emphasizes the need to gather further evidence to ascertain the biological behavior of this emerging entity.

NIPBL::NACC1 Fusion Hepatic Carcinoma.

Several reports describing a rare primary liver tumor with histologic features reminiscent of follicular thyroid neoplasms have been published under a variety of descriptive terms including thyroid-like, solid tubulocystic, and cholangioblastic cholangiocarcinoma. Although these tumors are considered to represent histologic variants, they lack classic features of cholangiocarcinoma and have unique characteristics, namely immunoreactivity for inhibin and NIPBL::NACC1 fusions. The purpose of this study is to present clinicopathologic and molecular data for a large series of these tumors to better understand their pathogenesis. We identified 11 hepatic tumors with these features. Immunohistochemical and NACC1 and NIPBL fluorescence in situ hybridization assays were performed on all cases. Four cases had available material for whole-genome sequencing (WGS) analysis. Most patients were adult women (mean age: 42 y) who presented with abdominal pain and large hepatic masses (mean size: 14 cm). Ten patients had no known liver disease. Of the patients with follow-up information, 3/9 (33%) pursued aggressive behavior. All tumors were composed of bland cuboidal cells with follicular and solid/trabecular growth patterns in various combinations, were immunoreactive for inhibin, showed albumin mRNA by in situ hybridization, and harbored the NIPBL::NACC1 fusion by fluorescence in situ hybridization. WGS corroborated the presence of the fusion in all 4 tested cases, high tumor mutational burden in 2 cases, and over 30 structural variants per case in 3 sequenced tumors. The cases lacked mutations typical of conventional intrahepatic cholangiocarcinoma. In this report, we describe the largest series of primary inhibin-positive hepatic neoplasms harboring a NIPBL::NACC1 fusion and the first WGS analysis of these tumors. We propose to name this neoplasm NIPBL:NACC1 fusion hepatic carcinoma.

Epithelioid trophoblastic tumor: A case series.

An epithelioid trophoblastic tumor (ETT) is an extremely rare gestational trophoblastic tumor. Cases of ETT present with abnormal vaginal bleeding in women of reproductive age group with marginally elevated beta human chorionic gonadotrophin (B-hCG) levels. Here, we describe a series of four patients (all were females) including histomorphology, immunoprofiles, and diagnostic difficulty of this rare entity. All cases were in their reproductive age group. The mean pre-treatment hCG level was 665.24 (mIU/mL). Microscopically, all cases had a tumor showing an epithelioid appearance arranged in large nests and sheets. Individual tumor cells were round to polygonal with abundant eosinophilic cytoplasm, with central vesicular nuclei and prominent nucleoli. Areas of hemorrhage, necrosis, and intercellular hyaline-like material deposition were identified in all cases (100%). Immunohistochemically, tumor cells in all cases showed diffuse positivity for AE1/AE3 and p63 (100%). GATA3 was available in one case (25%), which was positive in the tumor cells. In one case (25%), hPL was focally positive, and in one case (25%), it was negative. SALL4 was performed in two cases (50%) and was negative in tumor cells. The mean Ki67 labeling index was 19.2 (range 10-30%). All four patients underwent surgical intervention and were treated with hysterectomy. The mean follow-up in this series was 39.4 months (range 6-70), and all patients are alive to date with a mean survival of 32.8 months (range, 4-67).

Remote Reporting from Home for Primary Diagnosis in Surgical Pathology: A Tertiary Oncology Center Experience during the COVID-19 Pandemic.

BACKGROUND: The COVID-19 pandemic accelerated the widespread adoption of digital pathology (DP) for primary diagnosis in surgical pathology. This paradigm shift is likely to influence how we function routinely in the postpandemic era. We present learnings from early adoption of DP for a live digital sign-out from home in a risk-mitigated environment. MATERIALS AND METHODS: We aimed to validate DP for remote reporting from home in a real-time environment and evaluate the parameters influencing the efficiency of a digital workflow. Eighteen pathologists prospectively validated DP for remote use on 567 biopsy cases including 616 individual parts from 7 subspecialties over a duration from March 21, 2020, to June 30, 2020. The slides were digitized using Roche Ventana DP200 whole-slide scanner and reported from respective homes in a risk-mitigated environment. RESULTS: Following re-review of glass slides, there was no major discordance and 1.2% (n = 7/567) minor discordance. The deferral rate was 4.5%. All pathologists reported from their respective homes from laptops with an average network speed of 20 megabits per second. CONCLUSION: We successfully validated and adopted a digital workflow for remote reporting with available resources and were able to provide our patients, an undisrupted access to subspecialty expertise during these unprecedented times.

Pleomorphic lipoma: A gentle giant of pathology.

Pleomorphic lipoma is a relatively rare adipocytic neoplasm, occurring predominantly in elderly males in the subcutaneous tissues of the neck or shoulder. To the best of our knowledge, only five cases have been reported in which the lesion was intramuscular. We hereby report a case of a 60-year-old female patient, presenting with an intramuscular, posterior shoulder mass. The aspirate showed a giant cell-rich lesion, admixed with short, plump-looking, spindly cells. There was no overt evidence of malignancy; however, the cell cytology was sufficiently atypical to warrant concern. Subsequent excision revealed a classical pleomorphic lipoma on histology with no evidence of malignancy. CD34 staining by immunohistochemistry further supported the diagnosis. Differential diagnosis and the cytological diagnostic pitfalls of pleomorphic lipomas have been discussed with a review of the literature.

In situ follicular neoplasia/lymphoma: three illustrative cases exemplifying unique disease presentations.

We report three elderly patients with follicular lymphoma in situ (FLIS) each highlighting a unique pattern of disease presentation and progression. The first patient had incidentally detected FLIS with peripheral blood spill and yet had an 11-year uneventful follow up. The second patient with an overt follicular lymphoma (FL) developed high-grade transformation in jejunum with FLIS extensively involving the Payers patches. The third patient had a FLIS but that qualified as higher grade and was treated in spite of lack of overt FL mainly because of higher grade and patient subsequently did develop overt FL. The first case of typical FLIS confirms that peripheral blood spill does not connote poor prognosis in FLIS, the second case illustrates that FLIS may colonize mucosa-associated lymphoid tissue as part of homing in process of a disseminated FL and the third case validates the aggressive nature of high-grade FLIS.