Nonsteroidal anti-inflammatory drug-induced small bowel strictures (diaphragm disease) - an under-recognized cause of small bowel obstruction.

BACKGROUND: Small bowel obstruction is a major source of morbidity and mortality that carries a significant economic burden. Recurrent small bowel obstruction may be secondary to circumferential strictures (small bowel diaphragm disease), an under-recognized entity secondary to long-term nonsteroidal anti-inflammatory drug (NSAID) use. We aimed to describe the sensitivity of preoperative computed tomography (CT) enterography in patients with surgically treated small bowel diaphragm disease. METHODS: We retrospectively reviewed adult patients who underwent elective small bowel resection for small bowel obstruction performed by a single minimally invasive surgeon between 2010 and 2023. Patient history, radiographic, endoscopic, operative, and pathology reports were reviewed for reference to NSAID use, small bowel strictures, diaphragms, and enteropathy. Exclusion criteria were prior radiation, inflammatory bowel disease, malignancy, adhesive disease, and anastomotic strictures. RESULTS: A total of 225 patients were identified, 22 (10%) of whom met the inclusion criteria. The mean age was 60.7 years (range 29-78), with 15 women (68%). All patients underwent minimally invasive small bowel resection for obstruction with histopathologic evidence of stricture without evidence of transmural inflammation, granuloma, or dysplasia and confirmed NSAID use (n = 22, 100%). Anemia was present in 36% (n = 8). Preoperative CT or magnetic resonance (MR) enterography was performed in 18 patients (82%), of which stricturing was reported in 13 (72%). Intraoperatively, palpation identified strictures in all patients. CONCLUSION: NSAID-induced small bowel injury is an under-recognized condition that, in severe cases, can present as small bowel obstruction. Surgeons should consider diaphragm disease in patients with obstruction and NSAID use, in which preoperative CT or MR enterography may be useful but cannot rule out disease.

Adenomyoepithelioma of the Breast: Radiologic-Pathologic Correlation and Management.

Adenomyoepithelioma (AME) is a rare, usually benign breast neoplasm with low potential for malignant transformation. Imaging features are nonspecific and overlap with other benign and malignant breast lesions. On mammography, AME most often presents as a mass, usually oval in shape, with variable reported margins. Less commonly, AME can present mammographically as an asymmetry or can be mammographically occult. Associated calcifications are uncommon. On US, AME is usually seen as a hypoechoic oval mass, but it can also manifest as a complex cystic and solid mass. On US, the majority of AME have noncircumscribed margins (indistinct, angular, or microlobulated). Internal vascularity is usually present, and posterior enhancement can be seen. Although there is limited literature on MRI features, the most frequent finding is an irregular mass with washout kinetics; T2 hyperintensity can be observed. These nonspecific and often suspicious imaging features usually merit biopsy. On histologic analysis, AME is characterized by a biphasic proliferation of myoepithelial and epithelial cells. Pathologic diagnosis can be difficult due to the variety of histologic features of AME and heterogeneity in these tumors, especially when sampling is limited, such as in core needle biopsies. Wide local surgical excision of AME is recommended due to potential for recurrence and malignant transformation.

Ductal Carcinoma Arising in a Squamous Epithelial Inclusion Cyst within an Axillary Lymph Node: A Challenging Nodal Metastasis.

Introduction. Assessment of axillary lymph nodes in breast carcinoma is an important part of staging to guide appropriate clinical management. Lymph node inclusions of different types, including nevoid, squamous, and glandular, are rare but have been reported in multiple different anatomic locations including the axilla. These can result in diagnostic challenges and pose risks of misdiagnoses. Rarely, malignancies may arise intrinsic to otherwise incidental benign nodal inclusions. Case Presentation. We report a case of ductal carcinoma diagnosed within a squamous epithelial inclusion cyst within an axillary lymph node in a patient with pure ductal carcinoma in situ (DCIS) of the ipsilateral right breast. To our knowledge, this is the fifth report in the literature of breast carcinoma confirmed within an axillary inclusion in a patient with pure DCIS. Evaluation of the primary DCIS and lymph node inclusions, by routine and immunohistochemical stains, was performed for assessment. Discussion. The presence of lymph node inclusions can pose a challenge in assessment of benignity and malignancy, on frozen and permanent histologic sections. Pathologists should carefully evaluate lymph node inclusions to ensure that intrinsic malignancies are not missed within rare otherwise benign appearing incidental epithelial rests.

Allowing Surgical Pathology Fellows to Release Preliminary Reports Increases Learner Independence and Satisfaction.

CONTEXT.­: Progressive independence in medicine is critical to building confidence and decisiveness in trainees. However, this can be difficult to accomplish in the strict regulatory environment of pathology. OBJECTIVE.­: To pilot and adopt a process whereby surgical pathology fellows independently manage a subset of cases and release preliminary reports. DESIGN.­: Upon program approval, board-certified surgical pathology fellows were eligible for preliminary report sign-out at their discretion. Eligible cases were sent from outside institutions for confirmatory review. Preliminary reports were viewable in the electronic medical record. Safety measures were used to ensure timely release of final reports by attending pathologists. RESULTS.­: Fellows participating in the pilot (n = 4) released 59 preliminary reports out of 101 cases reviewed (58%), with 1 potentially significant discrepancy between preliminary and final report. Turnaround time was not affected. The process was endorsed by all participants and adopted as standard practice. During the first year, eligible fellows (n = 8) released 123 preliminary reports out of 1260 cases reviewed (9.8%). There were no major diagnostic discrepancies and no effects on turnaround time. The number of preliminary reports released by each fellow was variable (range, 2-48; median, 8), likely a reflection of both external factors (number of trainees on service, volume) and trainee-specific factors (confidence, efficiency). CONCLUSIONS.­: Fellows showed good judgment when independently managing cases, with just 1 potentially significant discrepancy out of 182 cases (<1%). No patients were adversely impacted. Use of this process varied widely among fellows and may require closer monitoring and encouragement for fellows who are tentative about releasing preliminary reports.

Eosinophilic mastitis mimicking a developing asymmetry.

Eosinophilic mastitis is a very rare form of mastitis with few reported cases in the literature. This is a case of eosinophilic mastitis in a 48-year-old woman which presented as a screen detected right breast developing asymmetry. No sonographic abnormalities were visualized on diagnostic workup, and subsequent tomosynthesis-guided biopsy was performed. Knowledge of this rare entity is helpful in the radiologic-pathologic correlation, diagnosis, and clinical management of future cases.

Response Rates of Invasive Lobular Cancer in Patients Undergoing Neoadjuvant Endocrine or Chemotherapy.

BACKGROUND: A gap remains in the role of neoadjuvant therapy for patients with ILC. METHOD: Single-institution retrospective review of patients with ILC who received neoadjuvant therapy between 2008 and 2019. RESULTS: 141 patients met inclusion criteria: 71 neoadjuvant chemotherapy (NACT) and 70 neoadjuvant endocrine therapy (NET). 7/71 (9.9%) patients had a pCR following NACT compared to 1/70 (1.4%) with NET (P = .063). pCR was observed in 5/18 (27.8%) patients with Her2Neu-positive disease following NACT, compared to 2/53 (3.8%) with Her2Neu-negative disease (P = .01).For luminal B tumors, median Ki-67 decrease was similar following NACT and NET (18.3 vs 16.3, P = .26).T category decreased in 59 (42.1%) patients following neoadjuvant therapy, increased in 9 (6.4%), and was unchanged in 72 (51.4%). More patients had an increase (28.6%) than decrease (12.1%) in their N category, including 13/60 (21.7%) who were clinically node-negative at diagnosis and identified to have node-positive disease following neoadjuvant therapy, at definitive surgery. CONCLUSION: In Her2Neu-negative ILC, the potential of a pCR with NACT or NET is low. Most patients' nodal status and tumor size remain unchanged. There is a potential for pathologic stage to be higher at surgery compared to the clinical stage prior to neoadjuvant therapy.

Pictorial Review of Common and Uncommon Pediatric Breast Lesions.

Breast masses in children and adolescents are uncommon, and the spectrum of pediatric breast masses is predominantly benign and different from that in adults. Knowledge of the clinical presentation and imaging features of the various stages of normal development and mass-forming lesions in the pediatric breast can guide a tailored imaging approach and help the radiologist make a definitive diagnosis. Breast development begins during fetal gestation along the embryologic milk lines and continues through puberty as the breast matures through the Tanner stages of development. Normal and developmental variants and benign neoplastic and nonneoplastic lesions in the pediatric breast are common causes of concern. Malignant breast masses in children are rare and are more often due to metastasis than primary breast cancer. When clinically warranted, US is the mainstay for imaging the pediatric breast and requires careful correlation of sonographic findings with patient age and history. Breast MRI can be used to further characterize lesions and evaluate the extent of disease. Biopsy should be considered only for suspicious findings and must be weighed against the risk of iatrogenic injury to the developing breast. Given that the majority of mass-forming lesions in the pediatric breast are benign, the diagnostic and management approach should emphasize "first do no harm." Knowledge of the imaging appearance of normal breast development and the spectrum of benign and malignant pediatric breast masses is necessary to make the correct diagnosis. © RSNA, 2022.

Lack of Clinical Value for Immunohistochemistry for Sentinel Lymph Node Assessment in Invasive Lobular Carcinoma.

BACKGROUND: The distinct histologic appearance of invasive lobular carcinoma (ILC) may pose diagnostic challenges for sentinel lymph node (SLN) analysis. We evaluated the impact of cytokeratin immunohistochemistry (IHC) on SLN assessment in ILC and its contribution to pathologic nodal upstaging. METHODS: We identified ILC patients treated with SLN surgery at our institution between September 2008 and August 2021. IHC for SLN assessment was employed at the discretion of the pathologist. Differences between groups evaluated with and without IHC were compared using Chi-square tests. RESULTS: Overall, 608 cases of ILC were identified in patients who underwent SLN surgery. IHC was used in 301 cases (49.5%) and was not associated with cT category, pT category, or tumor grade. Use of IHC increased detection of SLN+ disease when isolated tumor cells (ITCs) were included in the analysis (35.9% with IHC vs. 21.2% without IHC; p < 0.001). There was no effect on nodal upstaging to micrometastatic disease (pN1mi) or greater (21.9% with IHC vs. 21.2% without IHC; p = 0.82). IHC did not increase the number of positive SLNs detected (median 1 with and without IHC) nor did it increase axillary lymph node dissection (ALND) rates (11.6% with IHC vs. 15.3% without IHC; p = 0.18). CONCLUSION: IHC improved detection of pN0(i+) disease among ILC patients undergoing SLN surgery. IHC did not increase upstaging to pN1mi or higher categories of nodal disease, detection of a greater number of positive SLNs, or ALND rates. Our data suggest routine use of IHC for SLN assessment in ILC patients does not add clinical utility.

Local Recurrence of Invasive Secretory Breast Carcinoma in a Gravid Patient Post-Mastectomy.

This is a case of locally recurrent invasive secretory carcinoma of the breast during pregnancy, detected as a palpable mass in the reconstructed right breast of a 32-year-old female at 24 weeks gestation. The patient was initially diagnosed with secretory carcinoma 8 years prior, for which she underwent nipple sparing mastectomy followed by adjuvant chemotherapy and endocrine therapy. Due to pregnancy, the recurrence was treated initially with conservative excision alone, followed by definitive management postpartum which included wide local excision, sentinel lymph node biopsy and adjuvant chest wall radiation. Secretory carcinoma of the breast is a rare cancer with a predilection for young age and indolent course. This case report describes an unusual case of recurrent secretory carcinoma, of interest due to both its diagnosis during pregnancy, and its recurrence after nipple sparing mastectomy.

Imaging features of adenosquamous carcinoma of the breast - A rare variant of metaplastic breast carcinoma.

Adenosquamous carcinoma of the breast is a rare subtype of metaplastic carcinoma, which accounts for <1% of invasive breast malignancy. Metaplastic carcinoma is usually high grade and aggressive with typically reported benign imaging features when compared to invasive ductal carcinoma. However, the adenosquamous variant is a subtype with a more favorable prognosis. Within the literature, there is limited imaging description with case studies focusing on metaplastic carcinoma. Herein, we report seven cases of the adenosquamous subtype describing the imaging findings with correlation to clinical history and pathology. The majority of patients (n = 6) presented with palpable breast masses. One patient was identified through screening mammography. Mammographically (n = 6), tumors appeared as irregular masses. Sonographically (n = 7), tumors appeared as irregular masses ranging from solid to mixed solid/cystic masses. On MRI (n = 1), one tumor appeared as an irregular rim enhancing mass. FDG PET/CT (n = 2) and whole-body bone scan (n = 1) were also available for review. The majority of tumors were low-grade (n = 6) with only one high-grade tumor. This case series of seven patients demonstrated predominantly suspicious imaging features despite the majority being low-grade tumors.

Laboratory Medicine and Pathology Education During the COVID-19 Pandemic-Lessons Learned.

The rapidly spreading COVID-19 pandemic demanded immediate organizational pivots in departments of laboratory medicine and pathology, including development and implementation of severe acute respiratory syndrome coronavirus 2 diagnostics in the face of unprecedented supply chain shortages. Laboratory medicine and pathology educational programs were affected in numerous ways. Here, we overview the effects of COVID-19 on the large, academic Department of Laboratory Medicine and Pathology educational practice at Mayo Clinic, highlighting lessons learned for the post-pandemic era and planning for the possibility of a future pandemic.

Characteristics and Spatially Defined Immune (micro)landscapes of Early-stage PD-L1-positive Triple-negative Breast Cancer.

PURPOSE: Programmed death ligand 1 [PD-(L)1]-targeted therapies have shown modest survival benefit in triple-negative breast cancer (TNBC). PD-L1+ microenvironments in TNBC are not well characterized and may inform combinatorial immune therapies. Herein, we characterized clinicopathologic features, RNA-based immune signatures, and spatially defined protein-based tumor-immune microenvironments (TIME) in early-stage PD-L1+ and PD-L1- TNBC. EXPERIMENTAL DESIGN: From a large cohort of chemotherapy-naïve TNBC, clinicopathologic features, deconvoluted RNA immune signatures, and intraepithelial and stromal TIME (Nanostring GeoMX) were identified in subsets of PD-L1+ and PD-L1- TNBC, as defined by FDA-approved PD-L1 companion assays. RESULTS: 228 of 499 (46%) TNBC were PD-L1+ (SP142: ≥1% immune cells-positive). Using PD-L1 22C3, 46% had combined positive score (CPS) ≥ 1 and 16% had CPS ≥10. PD-L1+ TNBC were higher grade with higher tumor-infiltrating lymphocytes (TIL; P < 0.05). PD-L1 was not associated with improved survival following adjustment for TILs and other variables. RNA profiles of PD-L1+ TNBC had increased dendritic cell, macrophage, and T/B cell subset features; and decreased myeloid-derived suppressor cells. PD-L1+ stromal and intraepithelial TIMEs were highly enriched in IDO-1, HLA-DR, CD40, and CD163 compared with PD-L1-TIME, with spatially specific alterations in CTLA-4, Stimulator of Interferon Genes (STING), and fibronectin. Macrophage- and antigen presentation-related proteins correlated most strongly with PD-L1 protein. CONCLUSIONS: In this early-stage TNBC cohort, nearly 50% were PD-L1+ (SP142 companion assay) while 16% were PD-L1+ with the 22C3 companion assay. PD-L1+ TNBC had specific myeloid-derived and lymphoid features. Spatially defined PD-L1+ TIME were enriched in several clinically actionable immune proteins. These data may inform future studies on combinatorial immunotherapies for patients with PD-L1+ TNBC.See related commentary by Symmans, p. 5446.

Vulvar apocrine hidradenocarcinoma arising in a hidradenoma papilliferum-A case report.

Hidradenoma papilliferum (HP) is a benign adnexal neoplasm of the vulva that typically presents as a unilateral, flesh-colored papule in the labium majus in middle-aged Caucasian women. It is considered to be a close counterpart of the intraductal papilloma of the breast. Malignant transformation is rare with few reports in the literature. We present a case of vulvar mammary-type apocrine hidradenocarcinoma arising in an HP.

Mammary and extramammary myofibroblastoma: multimodality imaging features with clinicopathologic correlation, management and outcomes in a series of 23 patients.

OBJECTIVE: The purpose of this study was to describe the imaging appearance, diagnosis, and management of mammary and extramammary myofibroblastoma (MFB) in a series of 23 patients. METHODS AND MATERIALS: Following institutional review board approval, cases were identified by searching for "myofibroblastoma" in radiology reports. Multimodality imaging and pathological features were assessed. RESULTS: 23 cases of myofibroblastoma were identified in 15 males and 8 females. Most cases were in the breast (20/23, 87%), presenting as a palpable mass or discovered incidentally on mammography in females or chest CT in males. Extramammary MFB lesions (3/23, 13%) presented with symptoms related to mass effect. At imaging, MFB most often demonstrated an oval or irregular mass that was hypoechoic or heterogeneously echogenic with variable margins. MRI showed T2 hyperintensity, diffusion restriction, and plateau kinetics. Extramammary MFB appeared as an enhancing mass with variable fat content and T2 intensity. CONCLUSION: Here we describe imaging and clinicopathological features of mammary and extramammary myofibroblastoma. ADVANCES IN KNOWLEDGE: Imaging description of this rare tumor is limited in the literature, and to date this is the largest case series describing the imaging findings.

Tiger-Striped PASH: Recognition of a Unique Morphology Allows for a Zippered-Up Diagnosis of Pseudoangiomatous Stromal Hyperplasia of Breast.

Pseudoangiomatous stromal hyperplasia (PASH) of the breast is histologically characterized by anastomosing and slit-like spaces invested by collagenous stroma and lined by flattened, spindle cells. These clear spaces that may mimic microscopic vascular channels do not contain red blood cells. Immunohistochemistry (IHC) studies may also help to confirm a diagnosis of PASH, with the spindled cells marking positively with CD34 and PR while demonstrating no reactivity with more specific endothelial antigens such as CD31 and ERG. In the current case, a 39-year-old female was diagnosed with cellular PASH of the right breast with unique histological patterns showing "tiger-striped" and "zippered" histologies. To our knowledge, this is the first report of these unique variant PASH morphologies.

Pathology of breast cancer in the last half century.

The past 50 years has been an era of technological innovation converging with the now dominant culture of testing hypotheses using clinical trials and case cohort methodology with rigorous statistical analysis. Great advances have been made in early diagnosis and, especially, less toxic and disfiguring primary therapy. Many of the advances in pathology have been in conjunction with efforts to support clinical initiatives, improve diagnostic reliability and translate basic science discoveries into tests that stratify patient management. Pathologists, with the support of epidemiologists, have lead significant advancements in the description and clinical significance of benign breast disease. Despite considerable efforts, the cure for breast cancer awaits better understanding of the pathophysiology of metastasis. We stand now at the brink a new era of technology, in which powerful genomic assays may be put to use in uncovering targets of therapy and defining mechanisms of disease progression. Pathologists must be active in ensuring that discoveries in this realm are optimized by assuring association with appropriate histological correlation and valid clinical endpoints.

Cytomorphology of ciliated foregut cyst of the pancreas.

Ciliated foregut cysts are benign congenital lesions that are commonly found in the mediastinum but are rare in the retroperitoneum. So far only very few cases of ciliated foregut cyst found in the pancreas have been reported, and less with cytologic findings described. We report a case of ciliated foregut cyst in pancreas in an asymptomatic patient diagnosed on fine needle aspiration cytology. We also discuss the cytology features that would help with the diagnosis, and the differential diagnosis that should be considered.