Dear readers of AJSP: Reviews and Reports,
I am delighted to present to you the second potpourri issue of 2020. It is our new tradition to have some issues of the journal devoted entirely to unsolicited peer-reviewed case reports. While we continue to publish our traditional, topic-centered issues of the journal, these unsolicited case reports will be also added to the thematic issues, as well as published online. As usual, all of these will have undergone a rigorous peer and editorial review and are selected to support the educational mission of the journal. This mission has always been to promote the education of practicing pathologists and trainees and to publish materials helpful in solving significant and common diagnostic dilemmas and avoiding important pitfalls.
For this issue, we chose to focus on several areas that are important clinical problems and require pathologist's input. We start with a group of diseases that straddle the divide between anatomic and clinical pathology and thrombotic microangiopathies. Drs Hardy and Stashek discuss the pathogenesis and spectrum of severity, as well as skin findings in these conditions. The next group of reviews focuses on rare but important entities and differential diagnostic dilemmas in renal tumor pathology: a comprehensive review of fumarate hydratase–deficient renal cell carcinoma by D. Chen and R. Virk; collision tumor composed of renal oncocytoma and mucinous tubular and spindle cell carcinoma by J. Roe and coauthors; and malignant perivascular epithelioid cell tumor (PEComa) mimicking renal cell carcinoma—a rare but important diagnostic pitfall. Clear cell tumors and their differential diagnosis always include renal cell carcinoma, but in this issue, D. Russell focuses our attention on ovarian tumors with clear cell features and their differential diagnosis with emphasis on challenges in the setting of a frozen-section diagnosis. Another tumor with occasional clear cell features is mesothelioma as seen in a case report of a peritoneal mesothelioma by O. Saeed et al.
The next 2 reports focus on such dangerous diagnostic pitfalls as adamantinoma masquerading as metastatic squamous cell carcinoma, presented and discussed in depth by K. Wieditz-Ooms and coauthors, and mesothelial cell inclusions in lymph nodes mimicking a metastatic malignancy by D. Stefanko and coauthors. These reports carefully walk the reader through the thought process and cues to the correct diagnosis in these types of cases.
The last 3 articles are devoted to problematic lesions of head and neck. The review of sinonasal mucoepidermoid carcinomas by Middleton and Manucha is thorough and beautifully illustrated; it is followed by a well documented case report of an aggressive glomus tumor of the head and neck by S. Bai and coauthors. An excellent report and review of primary extranodal Hodgkin lymphoma of the sphenoid sinus concludes this issue.
As the goal of our journal has always been to promote the education of practicing pathologists and trainees, we attempted to select articles, which would raise awareness of rare entities, unusual presentations, and important pitfalls. We hope that this issue achieved its goal and that you will have learned new information useful in your practice or training.