An automated histological classification system for precision diagnostics of kidney allografts.

For three decades, the international Banff classification has been the gold standard for kidney allograft rejection diagnosis, but this system has become complex over time with the integration of multimodal data and rules, leading to misclassifications that can have deleterious therapeutic consequences for patients. To improve diagnosis, we developed a decision-support system, based on an algorithm covering all classification rules and diagnostic scenarios, that automatically assigns kidney allograft diagnoses. We then tested its ability to reclassify rejection diagnoses for adult and pediatric kidney transplant recipients in three international multicentric cohorts and two large prospective clinical trials, including 4,409 biopsies from 3,054 patients (62.05% male and 37.95% female) followed in 20 transplant referral centers in Europe and North America. In the adult kidney transplant population, the Banff Automation System reclassified 83 out of 279 (29.75%) antibody-mediated rejection cases and 57 out of 105 (54.29%) T cell-mediated rejection cases, whereas 237 out of 3,239 (7.32%) biopsies diagnosed as non-rejection by pathologists were reclassified as rejection. In the pediatric population, the reclassification rates were 8 out of 26 (30.77%) for antibody-mediated rejection and 12 out of 39 (30.77%) for T cell-mediated rejection. Finally, we found that reclassification of the initial diagnoses by the Banff Automation System was associated with an improved risk stratification of long-term allograft outcomes. This study demonstrates the potential of an automated histological classification to improve transplant patient care by correcting diagnostic errors and standardizing allograft rejection diagnoses.ClinicalTrials.gov registration: NCT05306795 .

Sporadic Hemangioblastoma of the Cavernous Sinus and Meckel's Cave.

Objectives To describe an extremely rare case of sporadic hemangioblastoma (HB) within the cavernous sinus and Meckel's cave with extension to the cerebellopontine angle (CPA) cistern. Methods A 73-year-old male presented with hearing loss, unilateral ptosis, and facial numbness. Results The imaging showed a complex cystic-solid mass centered at the left cavernous sinus and Meckel's cave with extension to the CPA cistern. Patient underwent retrosigmoid craniectomy for partial resection of the CPA angle component of the mass. Surgical pathology confirmed the diagnosis of HB and patient was scheduled for subsequent radiotherapy of the residual mass. Conclusions We present an exceptional case of supratentorial HB without associated von Hippel-Lindau (VHL) disease, which was predominantly located in the cavernous sinus and Meckel's cave and led to multiple cranial nerve symptoms. We describe imaging characteristics and radiologic-pathologic correlation of this atypically located HB, which can be difficult to consider in the differential diagnosis presurgically.

Lipoma arborescens of the bicipitoradial bursa.

Lipoma arborescens (LA) is a rare, benign articular lesion that is most commonly found within the suprapatellar recess of the knee. An extremely rare case of LA involving unilateral bicipitoradial bursa is described in this study. A 58-year-old male presented with a superficial soft mass on the volar aspect of the left forearm. The magnetic resonance imaging (MRI) examination demonstrated a lobulated complex mass containing multiple frond-like fatty nodules, along the distal biceps tendon in the bicipitoradial bursa. Ultrasound-guided biopsy of the lesion confirmed the diagnosis of LA and patient was scheduled for surgical excision. Recognizing the characteristic imaging of LA, particularly on MRI, is essential for accurate pre-procedural diagnosis.

Hematologic Malignancies Discovered on Investigation of Breast Abnormalities.

OBJECTIVES: Hematological malignancies of the breast share a presentation similar to primary breast carcinomas but differ substantially in therapeutic approach and clinical outcomes. In this study, we investigate the frequency of hematological malignancies, their relative primary and secondary occurrences, and further characterize the distinct histopathologies of these malignancies with a special focus on lymphomas. To our knowledge this is one of the largest and most comprehensive studies of breast hematologic malignancies. METHODS: We conducted a retrospective review of our institution's pathology database for hematologic neoplasms diagnosed in breast tissue during a period of 22 years (1992-2014). Clinical characteristics, patient history, histologic subtype, and patient outcomes were analyzed. RESULTS: We identified 52 cases; 46 lymphomas, 4 plasmacytomas, and 2 myeloid sarcomas. The lymphoma cases were 15 diffuse large B-cell lymphomas (DLBCLs), 14 follicular lymphomas (FLs), 8 marginal zone lymphomas (MZLs), 2 anaplastic large T-cell lymphomas, 2 peripheral T-cell lymphomas-not otherwise specified, 1 each of small lymphocytic lymphoma, Burkitt lymphoma, mantle cell lymphoma, B-cell lymphoblastic lymphoma, and T-cell lymphoblastic lymphoma. In total, 30 cases were primary and 22 cases were secondary to the breast. Primary lymphomas accounted for 60% of lymphomas. Most FLs and almost all MZLs were primary. CONCLUSIONS: Primary hematological malignancies of the breast are more common than secondary: 58 % versus 42%. This finding is more evident in lymphomas: 63% versus 37%. The most common hematological malignancy in our study was DLBCL, followed by FL and MZL. Most FLs and almost all MZLs were primary. At the same time, the percentage of primary DLBCLs in our study is lower than the percentage reported in previous studies. We suggest that this could be the result of transformation from low-grade lymphomas. Although rare, hematological malignancies of the breast warrant a higher level of clinical suspicion as they present similarly to breast carcinomas but require a substantially different therapeutic approach.

Spectrum of Clinicopathological Deviations in Long-Segment Hirschsprung Disease Compared With Short-Segment Hirschsprung Disease: A Single-Institution Study.

Hirschsprung disease (HSCR) is a congenital disorder characterized by intestinal aganglionosis leading to pseudoobstruction. The majority of cases are limited to the rectum or rectosigmoid (S-HSCR). A variably longer segment can be affected (L-HSCR), which may show many deviations from S-HSCR. We retrospectively reviewed 48 clinicopathologically confirmed total cases of HSCR at a single institution in a 21-year period to identify L-HSCR cases and determine their deviations from known features of S-HSCR. Eight L-HSCR cases were found where aganglionosis extended to the terminal ileum (7/8) or to the splenic flexure (1/8). L-HSCR lacked male preponderance and was in contrast more common in females (6/8). Associated anomalies included congenital heart disease (2) and neonatal hypothyroidism (1), previously underreported associations. The clinical diagnosis of L-HSCR was often delayed (average age at diagnosis 13 days) and the diagnosis was more often made operatively (5/8) rather than on rectal suction biopsy (3/8). Histologically, apart from aganglionosis, neural hyperplasia was either absent or focal, compounding the diagnostic difficulty. Although the number of cases in our study was limited due to the rarity of L-HSCR, this study still highlights the spectrum of deviations of L-HSCR from known clinicopathological features of S-HSCR.

Cytologic features of the normal pineal gland on squash preparations.

As primary pineal lesions are extremely rare, many surgical pathologists are unfamiliar with normal pineal cytologic features. We describe cytologic features of the normal pineal gland in patients of varying ages and identify common diagnostic pitfalls. We performed a retrospective review of pineal gland biopsies performed at our institution, where approximately 30,000 surgical specimens are accessioned yearly, for the last 23 years. Only two pineal gland biopsies were found. Although both cases were initially diagnosed as low-grade gliomas on frozen section, the final diagnosis was benign pineal tissue based on light microscopy and immunohistochemistry results. Additionally, we performed squash preparations of five normal pineal gland autopsy specimens with Papanicolaou and Diff-Quik® (Dade Behring, Newark, DE) stains. Infant preparations were highly cellular smears composed of numerous, uniform, single cells with indistinct cytoplasm, small round-to-oval nuclei, fine chromatin, and absent nucleoli and calcifications. The vague microfollicular pattern mimicked a pineocytoma and the fine fibrillary background mimicked a glial neoplasm. Young adult smears were similar; however, microcalcifications were present with fewer background single cells. Older patients had much less cellular smears composed of small clusters of cells with fusiform-to-spindle nuclei, a fine chromatin pattern, and indistinct cytoplasmic borders. There were fewer background single cells and more microcalcifications. The cytologic features of the native pineal gland vary with age. Normal pineal tissue can be confused with a pineocytoma or low-grade glioma. Familiarity with normal pineal gland cytological features will help to avoid a potential misdiagnosis.