A tip-predominant distribution of villous intraepithelial lymphocytes is not specific to celiac disease in children with Marsh I lesions.

OBJECTIVES: To assess if the distribution of villous intraepithelial lymphocytes (IELs) in a pediatric cohort with Marsh I histopathology is specific to celiac disease (CeD). METHODS: Multicenter, retrospective case-control study between January 2001 and December 2019 in children (<18 years) with and without CeD with intraepithelial lymphocytosis and normal villous architecture. Pathology specimens were reviewed by 2 study pathologists who were blinded to the final diagnosis. Morphologic features (villous height to crypt depth ratio [Vh:Cd]) and IELs in the villous tip, top, or bottom half of the villus were quantified. RESULTS: Of the 97 children with Marsh I histopathology identified during the study period, 63 were excluded due to an insufficient number of well-oriented villous-crypt complexes or a Vh:Cd less than 2. Villous IELs were measured in 34 cases (14 CeD, 20 non-CeD controls). There was no difference between the non-CeD and CeD groups in the mean IELs at the villous tip (14.0 ± 7.1 vs 11.7 ± 6.0, P = .31), top (46.4 ± 18.4 vs 38.3 ± 10.8, P = .11), or bottom (29.8 ± 16.8 vs 28.5 ± 12.8, P = .80) half of each villus, respectively. CONCLUSIONS: The distribution of IELs in Marsh I lesions is not specific for CeD.

Gross and Histologic Placental Abnormalities Associated With Neonatal Hypoxic-Ischemic Encephalopathy.

OBJECTIVE: To elucidate particular placental pathology findings that are associated with hypoxic ischemic encephalopathy (HIE) and determine which patterns are associated with adverse fetal/neonatal outcomes. STUDY DESIGN: Multi-institutional retrospective case-control study of newborns with HIE (2002-2022) and controls. Four perinatal pathologists performed gross and histologic evaluation of placentas of cases and controls. RESULTS: A total of 265 placentas of neonates with HIE and 122 controls were examined. Infants with HIE were more likely to have anatomic umbilical cord abnormalities (19.7% vs 7.4%, P = .003), fetal inflammatory response in the setting of amniotic fluid infection (27.7% vs 13.9%, P = .004), and fetal vascular malperfusion (30.6% vs 9.0%, P = <.001) versus controls. Fetal vascular malperfusion with maternal vascular malperfusion was more common in those who died of disease (P = .01). CONCLUSION: Placental pathology examination of neonates with HIE may improve our understanding of this disorder and its adverse outcomes.

Prostatic metaplasia and pilar differentiation in gender-affirming mastectomy specimens.

With the increasing practice of gender-affirming mastectomy as a therapeutic procedure in the setting of gender dysphoria, there has come a profusion of literature on the pathologic findings within these specimens. Findings reported in over 1500 patients have not included either prostatic metaplasia or pilar metaplasia of breast epithelium. We encountered both of these findings in the course of routine surgical pathology practice and therefore aimed to analyze these index cases together with a retrospective cohort to determine the prevalence, anatomic distribution, pathologic features, and associated clinical findings of prostatic metaplasia and pilar metaplasia in the setting of gender-affirming mastectomy. In addition to the 2 index cases, 20 additional archival gender-affirming mastectomy specimens were studied. Before mastectomies, all but 1 patient received testosterone cypionate, 6/22 patients received norethindrone, and 21/22 practiced breast binding. Prostatic metaplasia, characterized by glandular proliferation along the basal layer of epithelium in breast ducts, and in one case, within lobules, was seen in 18/22 specimens; 4/22 showed pilar metaplasia, consisting of hair shafts located within breast ducts, associated with squamoid metaplasia resembling hair matriceal differentiation. By immunohistochemistry, prostatic metaplasia was positive for PSA in 16/20 cases and positive for NKX3.1 in 15/20 cases. Forty-three reduction mammoplasty control cases showed no pilar metaplasia and no definite prostatic metaplasia, with no PSA and NKX3.1 staining observed. We demonstrate that prostatic metaplasia and pilar metaplasia are strikingly common findings in specimens from female-assigned-at-birth transgender patients undergoing gender-affirming mastectomy. Awareness of these novel entities in the breast is important, to distinguish them from other breast epithelial proliferations and to facilitate accrual of follow-up data for better understanding their natural history.

Pathology Trainee Redeployment and Education During the COVID-19 Pandemic: An Institutional Experience.

Pathology training programs throughout the United States have endured unprecedented challenges dealing with the ongoing coronavirus disease 2019 pandemic. At Houston Methodist Hospital, the Department of Pathology and Genomic Medicine planned and executed a trainee-oriented, stepwise emergency response. The focus was on optimizing workflows among areas of both clinical and anatomic pathology, maintaining an excellent educational experience, and minimizing trainee exposure to coronavirus disease 2019. During the first phase of the response, trainees were divided into 2 groups: one working on-site and the other working remotely. With the progression of the pandemic, all trainees were called back on-site and further redeployed within our department to meet the significantly increased workload demands of our clinical laboratory services. Adjustments to trainee educational activities included, among others, the organization of a daily coronavirus disease 2019 virtual seminar series. This series served to facilitate communication between faculty, laboratory managers, and trainees. Moreover, it became a forum for trainees to provide updates on individual service workflows and volumes, ongoing projects and research, as well as literature reviews on coronavirus disease 2019-related topics. From our program's experience, redeploying pathology trainees within our department during the coronavirus disease 2019 pandemic resulted in optimization of patient care while ensuring trainee safety, and importantly, helped to maintain continuous high-quality education through active involvement in unique learning opportunities.