Incidental Metaplastic Primary Pulmonary Meningioma.

Primary pulmonary meningioma is a rare benign tumor usually presenting as a solitary pulmonary nodule or mass. It can be easily misinterpreted as a primary lung tumor or metastases on imaging studies. We present a 54-year-old woman with an incidentally discovered solitary lung nodule, which was diagnosed as metaplastic primary pulmonary meningioma following resection. Metaplastic meningioma is a rare WHO grade 1 meningioma subtype with focal or global mesenchymal differentiation. To the authors' knowledge, primary pulmonary meningioma with mesenchymal differentiation has not been described previously in the English literature.

Immunoglobulin G4-Related Disease-Associated Dermatitis with Pruritus: A Positive Response to Dupilumab.

Immunoglobulin G4-related disease (IgG4-RD) is a rare fibro-inflammatory condition characterized by IgG4-expressing plasma cell infiltration of the skin and other organs, leading to profound itchiness. Oral corticosteroids are the first-line therapy for IgG4-RD but relapses and potential side effects are common. In this case, we discuss a patient with a hyperpigmented, scaling dermatitis on his arms, back, and chest with lichen amyloidosis (LA) that incompletely responded to corticosteroids. He had reduced quality of life secondary to chronic pruritus. Dupilumab, an IL-4 and IL-13 inhibitor, was initiated. He experienced a transient worsening, followed by complete resolution of his itch with remission of his rash. While the pathogenesis of IgG4-RD is not entirely understood, a T-helper 2 (Th2) immune response has been implicated, with interleukins (IL) 4, 5, 10, and 13 playing a role in IgG4 class switch, resulting in eosinophilia and elevated IgE. The strong response of dupilumab in this case may provide evidence in favor of the involvement of IL-4 and IL-13 in the pathogenesis of cutaneous IgG4-RD. Future clinical studies involving larger patient populations may be warranted.

Histologic Screening of Malignant Melanoma, Spitz, Dermal and Junctional Melanocytic Nevi Using a Deep Learning Model.

OBJECTIVE: The integration of an artificial intelligence tool into pathologists' workflow may lead to a more accurate and timely diagnosis of melanocytic lesions, directly patient care. The objective of this study was to create and evaluate the performance of such a model in achieving clinical-grade diagnoses of Spitz nevi, dermal and junctional melanocytic nevi, and melanomas. METHODS: We created a beginner-level training environment by teaching our algorithm to perform cytologic inferences on 136,216 manually annotated tiles of hematoxylin and eosin-stained slides consisting of unequivocal melanocytic nevi, Spitz nevi, and invasive melanoma cases. We sequentially trained and tested our network to provide a final diagnosis-classification on 39 cases in total. Positive predictive value (precision) and sensitivity (recall) were used to measure our performance. RESULTS: The tile-classification algorithm predicted the 136,216 irrelevant, melanoma, melanocytic nevi, and Spitz nevi tiles at sensitivities of 96%, 93%, 94% and 73%, respectively. The final trained model was able to correctly classify and predict the correct diagnosis in 85.7% of unseen cases (n = 28), reporting at or near screening-level performances for precision and recall of melanoma (76.2%, 100.0%), melanocytic nevi (100.0%, 75.0%), and Spitz nevi (100.0%, 75.0%). CONCLUSIONS: Our pilot study proves that convolutional networks trained on cellular morphology to classify melanocytic proliferations can be used as a powerful tool to assist pathologists in screening for melanoma versus other benign lesions.

DICER1-associated metastatic abdominopelvic primitive neuroectodermal tumor with an EWSR1 rearrangement in a 16-yr-old female.

We report a case of a DICER1-associated EWSR1-rearranged malignant primitive neuroectodermal tumor (PNET) arising in a patient with DICER1 tumor predisposition syndrome. A 16-yr-old female with a history of multinodular goiter presented with a widely metastatic abdominal small round blue cell tumor with neuroectodermal differentiation. EWSR1 gene rearrangement was identified in the tumor by fluorescence in situ hybridization (FISH). Genetic analysis revealed biallelic pathogenic DICER1 variation. The patient was treated with an aggressive course of chemotherapy, surgery, and radiation with complete pathologic response. We believe this case to represent a new expression of the DICER1 tumor predisposition syndrome, an entity caused by deleterious germline mutations in the DICER1 gene, encoding a ribonuclease active in the processing of miRNA. Patients with germline mutations in DICER1 develop a diverse group of benign and malignant tumors. Some of these tumors have been noted to have immature neuroepithelium as a component, including the ciliary body medulloepithelioma and the recently described DICER1-associated presacral malignant teratoid neoplasm. To our knowledge, abdominal sarcomas that resemble PNET histology with an EWSR1 rearrangement have not previously been described as a classical expression of the DICER1 syndrome phenotype.

Diffuse dermal angiomatosis associated with calciphylaxis: A 5-year retrospective institutional review.

BACKGROUND: Although diffuse dermal angiomatosis (DDA), a rare acquired reactive cutaneous vascular disorder, has been previously reported in association with calciphylaxis (CP), the clinical significance of this relationship has not yet been elucidated. METHODS: A total of 24 cases of CP diagnosed from 2013 to 2018 were retrospectively reviewed for the presence of associated DDA. Pertinent clinical information for each patient was also collected, and statistical analysis was performed using multivariable logistic regression, Student t test and Fisher exact test. RESULTS: African American race and comorbid congestive heart failure were the only variables that demonstrated independent, statistically significant association with the presence of DDA. End-stage renal failure, diabetes mellitus, immunosuppressive and hypercoagulable states, arrhythmia, body mass index, hypertension, coronary artery disease, patient age, duration of CP symptoms, gender, time interval from biopsy to death, anticoagulation therapy and sodium thiosulfate administration at the time of biopsy did not demonstrate a statistically significant association with DDA. CONCLUSION: DDA does not appear to be associated with disease severity or prognosis in cases of CP; however, in our population CP with concurrent DDA was more prevalent in African Americans and individuals with congestive heart failure.

Success in Implementation of a Resident In-Service Examination Review Series.

OBJECTIVES: Primary pathology board certification has been correlated with senior resident in-service examination (RISE) performance. We describe our success with an annual, month-long review series. METHODS: Aggregate program RISE performance data were gathered for 3 years prior to and 3 years following initiation of the review series. In addition, mean United States Medical Licensing Examination Step 1 and 2 Clinical Knowledge scores for residents participating in each RISE examination were obtained to control for incoming knowledge and test-taking ability. Linear models were used to evaluate differences in average RISE performance prior to and following the initiation of the review series in addition to controlling for relevant covariates. RESULTS: Significant improvement was noted in the grand total, anatomic pathology section average, clinical pathology section average, and transfusion medicine section. Although not statistically significant, improvement was noted on the cytopathology and clinical chemistry sections. There was no significant difference in scores in hematopathology, molecular pathology, and the special topics section average. In addition, improvement in primary pathology board certification rates was also noted. CONCLUSIONS: Institution of a month-long RISE review series demonstrated improved overall performance within our training program. The success could easily be replicated in any training program without significant disruption to an annual didactic series.

Intraneural Granular Cell Tumor of a Cervical Dorsal Nerve Root: A Case Report and Review of the Literature.

BACKGROUND: Granular cell tumor (GCT) is a relatively uncommon predominantly benign lesion that usually presents as a solitary, painless cutaneous or submucosal nodule. Most of these tumors are found in the tongue. Although GCT is believed to have a Schwann cell origin, reports of GCT in peripheral and spinal nerves are uncommon. CASE DESCRIPTION: We report the case of a 43-year-old man with neck pain and hand numbness who was found to have a heterogeneously enhancing left-sided C2 nerve sheath tumor on magnetic resonance imaging. He underwent C2 decompression and resection of the left-sided C2 nerve sheath tumor with subsequent C1-C2 arthrodesis and instrumentation. Histopathologic review showed GCT. Review of the literature yielded 4 other reported cases of GCT within the vicinity of a spinal nerve root. Only one of these explicitly showed spinal nerve root involvement. This is a rare case of a GCT presenting as cervical nerve root mass, and what we believe is the first reported case of this in the literature. CONCLUSIONS: The surgeon should be aware of GCT when encountering spinal nerve root tumors because it may alter the surgical approach necessary for adequate resection compared with more commonly encountered nerve sheath tumors.

Benign soft tissue lesions that may mimic malignancy.

Soft tissue lesions which mimic malignancy (pseudosarcomas), represent a significant diagnostic challenge for pathologists. Many features often associated with malignancy including rapid and infiltrative growth, increased cellularity and mitotic activity, and nuclear pleomorphism are present in benign and reactive conditions. This review highlights repair reactions including nodular fasciitis, proliferative fasciitis/myositis, intravascular papillary endothelial hyperplasia, and fat necrosis; lipoma and spindle cell/pleomorphic lipoma; fibroepithelial stromal (pseudosarcomatoid) polyp; phosphaturic mesenchymal tumor; and myxoma. While not inclusive of every pseudoneoplastic soft tissue lesion, this review emphasizes important diagnostic pitfalls and stresses the value of clinical, pathologic, and radiologic correlation.

"Low-Fat" Pseudoangiomatous Spindle Cell Lipoma: A Rare Variant With Loss of 13q14 Region.

Spindle cell and pleomorphic lipoma constitute a spectrum of lipomatous lesions with characteristic clinical, morphologic, immunohistochemical, and molecular features. Multiple variants have been previously described including vascular, fibrous, plexiform, and those with significantly less fat termed "low-fat" and "fat-free" by Folpe. Cytogenetically, spindle cell lipomas frequently display monoallelic loss of 13q14 region, an abnormality also found in cellular angiofibroma and mammary-type myofibroblastoma. Pseudoangiomatous spindle cell lipoma, originally described by Fletcher et al in 1994, is a rare variant within the spindle cell/pleomorphic lipoma spectrum, with less than 20 published cases. It consists of an admixture of spindle cells, "ropey" collagen, variable amounts of mature fat, and irregular, branching slit-like vascular spaces. The authors present a case of a 1-cm subcutaneous lesion excised from the neck of a 70-year-old man with classic histologic and immunohistochemical features of "low-fat" pseudoangiomatous spindle cell lipoma. Fluorescence in situ hybridization demonstrated a loss of 13q14 region, a characteristic presumed cytogenetic finding of spindle cell lipoma, which has been previously unconfirmed in this variant.