Utility of Retrospective Molecular Analysis in Diagnostically Challenging Mesenchymal Neoplasms.

Introduction: Molecular analysis plays a growing role in the diagnosis of mesenchymal neoplasms. The aim of this study was to retrospectively apply broad, multiplex molecular assays (a solid tumor targeted next-generation sequencing [NGS]) assay and single nucleotide polymorphism [SNP] microarray) to selected tumors, exploring the current utility and limitations. Methods: We searched our database (2010-2020) for diagnostically challenging mesenchymal neoplasms. After histologic review of available slides, tissue blocks were selected for NGS, SNP microarray, or both. DNA and RNA were extracted using the AllPrep DNA/RNA FFPE Kit Protocol on the QIAcube instrument. The NGS platform used was the TruSight Tumor 170 (TST-170). For SNP array, copy number variant (CNV) analysis was performed using the OncoScanTM CNV Plus Assay. Results: DNA/RNA was successfully extracted from 50% of tumors (n = 10/20). Specimens not successfully extracted included 6 core biopsies, 3 incisional biopsies, and 1 resection; 4 were decalcified (3 hydrochloric acid, 1 ethylenediaminetetraacetic acid). Higher tumor proportion and number of tumor cells were parameters positively associated with sufficient DNA/RNA extraction whereas necrosis and decalcification were negatively associated with sufficient extraction. Molecular testing helped reach a definitive diagnosis in 50% of tumors (n = 5/10). Conclusions: Although the overall utility of this approach is limited, these molecular panels can be helpful in detecting a specific "driver" alteration.

Retrospective Evaluation of the Antibody Prevalence in Epilepsy and Encephalopathy (APE2) Score.

BACKGROUND: Autoimmune encephalitis (AE) is a rare collection of disorders that present with a diverse and often nebulous set of clinical symptoms. Indiscriminate use of multi-antibody panels decreases their overall utility and predictive value. Application of a standardized scoring system may help reduce the number of specimens that generate misleading or uninformative results. METHODS: The results of autoimmune encephalopathy, epilepsy, or dementia autoantibody panels performed on serum (n = 251) or cerebrospinal fluid (CSF) (n = 235) specimens from October 9th, 2016 to October 11th, 2019 were collected. Retrospective chart review was performed to calculate the Antibody Prevalence in Epilepsy and Encephalopathy (APE2) score for patients with an antibody above the assay-specific reference interval and to classify results as true or false positive. RESULTS: Of the 486 specimens, 60 (12.3%) generated positive results for any AE antibody (6 CSF and 54 serum). After removing 2 duplicate specimens collected from a single patient, 10 of the remaining 58 were determined to be true positives and 8 contained neural-specific antibodies. Application of the APE2 score revealed that 89% of all true positives and 86% of specimens with neural-specific antibodies had a score ≥4. In contrast, 76% of false positives, 74% of clinically nonspecific antibodies, and 85% of the negative specimens had an APE2 score <4. CONCLUSION: The APE2 score can improve the diagnostic utility of autoimmune encephalopathy evaluation panels.

Acute myeloid leukemia with hepatic infiltration presenting as obstructive jaundice.

We present the case of a 55-year-old woman who presented with laboratory studies concerning for acute myeloid leukemia (AML) as well as obstructive cholestasis. In similar previously reported cases, concerns of chemotherapy toxicity exacerbated by liver dysfunction or concerns of untreated, concurrent cholecystitis in a neutropenic patient often delay initiation of chemotherapy for full medical workup. At admission, our patient was started on the cytoreductive agent hydroxyurea. By day 10 of her medical workup, her liver function had improved with total bilirubin levels normalizing. At that time, full-dose 7 + 3 induction with cytarabine and daunorubicin was then initiated.

Overcoming Educational Challenges and Impact of COVID-19 in a Pathology Residency Program.

Our program in is a 4-year combined anatomic pathology (AP) and clinical pathology (CP) program located in New Hampshire. Prior to the novel coronavirus (COVID-19) pandemic, double-headed sign-outs and multi-headed scope didactic conferences took place daily. On the autopsy service, cases were performed in-house under attending supervision, and forensic cases were performed at the off-site Office of the Medical Examiner. In CP, residents engaged in weekly didactic CP lectures and engaged in in-person resident-attending discussions, laboratory rounds, and direct patient contact on a daily basis. Institutional Universal Guidelines from the Emergency Order from New Hampshire were imposed at the beginning of the pandemic. These included exposure mitigation and employee screening strategies. Changes to resident rotations and didactic sessions, strategies to maintain resident wellness, and the program director perspectives are described. Amid the pandemic, digital pathology, teleconferencing platforms, and social media became important resources for pathology education. Digital platforms allowed groups of people to communicate and watch live presentations while social distancing. In AP, whole slide imaging allowed both attendings and residents to scan slides for personal learning, slide conferences, and didactic learning sessions. Following these measures, we supported the clinical needs of our medical center and learning needs of our residents while enacting social distancing and prevention guidelines early in the pandemic. Although the full impact of COVID-19 on pathology residency programs is still unknown, we incorporated new facets of communication technologies. These were immensely helpful in maintaining social distancing and helping to reduce the spread of disease.

Plasma cell variant of Castleman lymphadenopathy presenting as an adrenal mass.

Adrenal masses are commonly found on radiographic studies performed for unrelated reasons. We report on a case of a non-functioning adrenal mass from which a needle biopsy showed a nonspecific infiltrate of polyclonal plasma cells and small lymphocytes. A definitive diagnosis of the plasma cell variant of Castleman lymphadenopathy was made only after surgical excision. While the hyaline vascular variant of Castleman lymphadenopathy has been identified in adrenal glands, this is the first report of the plasma cell variant in an adrenal mass. This case particularly underscores the importance of an excisional biopsy for proper diagnosis.

Metastatic low-grade endometrial stromal sarcoma after 24 years: A case report and review of recent molecular genetics.

Low-grade endometrial stromal sarcoma (LGESS) is a rare malignant uterine tumor with the potential to metastasize years after the primary resection. There is a broad differential diagnosis for endometrial stromal sarcomas (ESS), including both benign and malignant entities. Herein, we present the case of a 64-year-old female with metastatic LGESS to the lung, diagnosed by cytology, 24 years after her initial presentation. This report discusses the cytomorphologic and histopathologic characteristics, and ancillary studies including immunohistochemical stains and recent advances in molecular diagnostics of ESS. Accurate diagnosis of spindle cell lesions in the lung can be challenging. As such, this case highlights the instrumental role of ancillary testing and molecular diagnostics to achieve a more definitive diagnosis.

A concise review of angiofibroma of soft tissue: A rare newly described entity that can be encountered by dermatopathologists.

Angiofibroma of soft tissue (AFST) is a newly described, rare mesenchymal neoplasm with fibroblastic and vascular components; it can be seen in both sexes and in a broad age range. It presents as a slowly enlarging mass, most often in the deep tissues of the upper and lower extremities, but occasionally in a superficial location where it may be encountered by dermatopathologists. It has a benign clinical course with a very low probability of recurrence after complete excision. This lesion has a prominent vasculature and may have an infiltrative growth pattern. These features could lead to a misdiagnosis, such as malignant vascular tumor, by an unwary dermatopathologist. The diagnosis of AFST initially relied solely on morphology and immunohistochemistry but, more recently, molecular studies have begun to play a role. Because of the potential for misdiagnosis, we present this review to raise awareness.