Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is the most common type of autoimmune encephalitis. Approximately 80% of patients with anti-NMDAR encephalitis are women. Tumors are detected in approximately 50% of female patients with anti-NMDAR encephalitis, of which 96% are ovarian teratomas. We describe the case of a 28-year-old woman diagnosed with anti-NMDAR encephalitis with mediastinal and bilateral ovarian teratomas in July 2019. The patient recovered following surgical management of the mediastinal mass and both ovarian teratomas, and immunotherapy. This case shows that teratomas can be found at multiple sites other than ovaries. Therefore, detecting teratomas using whole-body evaluation may be helpful for diagnosis and treatment.

Pulmonary epithelioid hemangioendothelioma (PEH) is a rare vascular tumor of borderline or low-grade malignancy, and its prognosis is unpredictable. Herein, we describe the case of a 47-year-old asymptomatic female with a diagnosis of multinodular PEH. During a 7-year followup, the nodules with large size and high 18F-fluorodeoxyglucose uptake in the initial study showed progression with increasing sizes; however, most small nodules (size < 1 cm) demonstrated spontaneous regression with peripheral rim or nodular calcification. The patient underwent surgical resection for an enlarged nodule. Of note, it is unusual for an individual to have mixed progression and regression concomitantly, which may be helpful in predicting the prognosis.

Cryptococcus neoformans is a fungus that primarily causes opportunistic infections in immunocompromised hosts. It can also cause various infections in immunocompetent patients. Pulmonary cryptococcosis involving the lymph node is relatively rare in immunocompetent patients. In this report, a previously healthy 17-year-old girl presented with high-grade fever and persistent cough. Chest X-ray and computed tomography (CT) scan revealed an anterior mediastinal conglomerate mass that expanded to the right supraclavicular area. Ultrasound-guided gun biopsy revealed histological evidence of cryptococcosis. Immunological screening tests did not identify immunodeficiency. She recovered completely with a combination therapy of amphotericin B and flucytosine for 2 weeks, followed by fluconazole for 8 months. The characteristics of cryptococcosis involving the mediastinal lymph node and the lung should be understood, and the possibility of cryptococcosis even in immunocompetent hosts should be considered.

A sarcomatoid variant of urothelial carcinoma in the female urethral diverticulum has not been reported previously. A 66-year-old woman suffering from dysuria presented with a huge urethral mass invading the urinary bladder and vagina. Histopathological examination of the resected specimen revealed predominantly undifferentiated pleomorphic sarcoma with sclerosis. Only a small portion of conventional urothelial carcinoma was identified around the urethral diverticulum, which contained glandular epithelium and villous adenoma. The patient showed rapid systemic recurrence and resistance to immune checkpoint inhibitor therapy despite high expression of programmed cell death ligand-1. We report the first case of urethral diverticular carcinoma with sarcomatoid features.

Molecular biomarker testing is the standard of care for non–small cell lung cancer (NSCLC) patients. In 2017, the Korean Cardiopulmonary Pathology Study Group and the Korean Molecular Pathology Study Group co-published a molecular testing guideline which contained almost all known genetic changes that aid in treatment decisions or predict prognosis in patients with NSCLC. Since then there have been significant changes in targeted therapies as well as molecular testing including newly approved targeted drugs and liquid biopsy. In order to reflect these changes, the Korean Cardiopulmonary Pathology Study Group developed a consensus statement on molecular biomarker testing. This consensus statement was crafted to provide guidance on what genes should be tested, as well as methodology, samples, patient selection, reporting and quality control.

A sarcomatoid variant of urothelial carcinoma in the female urethral diverticulum has not been reported previously. A 66-year-old woman suffering from dysuria presented with a huge urethral mass invading the urinary bladder and vagina. Histopathological examination of the resected specimen revealed predominantly undifferentiated pleomorphic sarcoma with sclerosis. Only a small portion of conventional urothelial carcinoma was identified around the urethral diverticulum, which contained glandular epithelium and villous adenoma. The patient showed rapid systemic recurrence and resistance to immune checkpoint inhibitor therapy despite high expression of programmed cell death ligand-1. We report the first case of urethral diverticular carcinoma with sarcomatoid features.

Molecular biomarker testing is the standard of care for non–small cell lung cancer (NSCLC) patients. In 2017, the Korean Cardiopulmonary Pathology Study Group and the Korean Molecular Pathology Study Group co-published a molecular testing guideline which contained almost all known genetic changes that aid in treatment decisions or predict prognosis in patients with NSCLC. Since then there have been significant changes in targeted therapies as well as molecular testing including newly approved targeted drugs and liquid biopsy. In order to reflect these changes, the Korean Cardiopulmonary Pathology Study Group developed a consensus statement on molecular biomarker testing. This consensus statement was crafted to provide guidance on what genes should be tested, as well as methodology, samples, patient selection, reporting and quality control.

Background: Urothelial carcinoma (UC) accounts for roughly 90% of bladder cancer, and has a high propensity for diverse differentiation. Recently, certain histologic variants of UC have been recognized to be associated with unfavorable clinical outcomes. Several UC studies have also suggested that tumor budding is a poor prognostic marker. Distant metastasis of UC after radical cystectomy is not uncommon. However, these metastatic lesions are not routinely confirmed with histology. Methods: We investigated the histopathologic features of 13 cases of UC with biopsy-proven distant metastases, with a special emphasis on histologic variants and tumor budding. Results: Lymph nodes (6/13, 46%) were the most common metastatic sites, followed by the lung (4/13, 31%), liver (4/13, 31%), and the adrenal gland (2/13, 15%). The histologic variants including squamous (n=1), micropapillary (n=4), and plasmacytoid (n=1) variants in five cases of UC. Most histologic variants (4/5, 80%) of primary UCs appeared in the metastatic lesions. In contrast, high-grade tumor budding was detected in six cases (46%), including one case of non-muscle invasive UC. Our study demonstrates that histologic variants are not uncommonly detected in distant metastatic UCs. Most histologic variants seen in primary UCs persist in the distant metastatic lesions. In addition, high-grade tumor budding, which occurs frequently in primary tumors, may contribute to the development of distant metastasis. Conclusions Therefore, assessing the presence or absence of histologic variants and tumor budding in UCs of the urinary bladder, even in non-muscle invasive UCs, may be useful to predict distant metastasis.

Cryptococcus neoformans is a fungus that primarily causes opportunistic infections in immunocompromised hosts. It can also cause various infections in immunocompetent patients. Pulmonary cryptococcosis involving the lymph node is relatively rare in immunocompetent patients. In this report, a previously healthy 17-year-old girl presented with high-grade fever and persistent cough. Chest X-ray and computed tomography (CT) scan revealed an anterior mediastinal conglomerate mass that expanded to the right supraclavicular area. Ultrasound-guided gun biopsy revealed histological evidence of cryptococcosis. Immunological screening tests did not identify immunodeficiency. She recovered completely with a combination therapy of amphotericin B and flucytosine for 2 weeks, followed by fluconazole for 8 months. The characteristics of cryptococcosis involving the mediastinal lymph node and the lung should be understood, and the possibility of cryptococcosis even in immunocompetent hosts should be considered.

Liquid biopsy for detection of mutation from circulating tumor DNA is a new technology which is attractive in that it is non-invasive. Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKI) is an effective first line drug for advanced non-small cell lung cancer patients who harbor activating EGFR mutation. During the course of treatment, resistance against TKI arises which can be contributed to EGFR T790M mutation in about 50–60% of patients. Third generation TKI may overcome the resistance. In patients who cannot undergo tissue biopsy due to variable reasons, liquid biopsy is an excellent alternative for the detection of EGFR T790M mutation. However, this relatively novel method requires standardization and vigorous quality insurance. Thus, a standard set of guideline recommendations for liquid biopsy for EGFR mutation testing suitable for the Korean medical community is necessary. In this article, we propose a set of provisional guideline recommendations that was discussed and approved by the Cardiopulmonary Pathology Study Group of the Korean Society of Pathologists.
Biopsy ; Carcinoma, Non-Small-Cell Lung ; DNA ; Genes, erbB-1 ; Humans ; Insurance ; Lung Neoplasms ; Lung ; Methods ; Pathology ; Protein-Tyrosine Kinases ; Receptor, Epidermal Growth Factor