Pleomorphic adenomas (PAs), the most common salivary gland tumors, are comprised of ductal epithelial and myoepithelial cells within a stromal background. A rare subset of PAs exhibits bizarre cells and 12q amplification involving HMGA2 and MDM2; in reported cases, bizarre cells have been confined to the myoepithelial component. We report the first case of a PA with bizarre-cytological features in both the ductal and myoepithelial components. A 75-year-old woman presented with a palatal mass. Histology revealed a well-circumscribed biphasic tumor with marked nuclear pleomorphism in both luminal ductal and non-luminal myoepithelial cells. Despite the alarming atypia, mitotic activity was low, and neither necrosis nor invasive growth was observed. Immunohistochemically, luminal bizarre cells exhibited ductal characteristics, whereas non-luminal bizarre cells exhibited myoepithelial characteristics. Tumor cells were negative for androgen receptor and HER2 and showed a p53 wild-type expression pattern. The Ki-67 labeling index was < 5%, and the bizarre cells rarely tested positive. Molecular analysis demonstrated amplification of HMGA2 and MDM2, whereas no other pathogenic variants related to salivary gland tumors were detected. Complete excision was performed; no evidence of recurrence or metastasis was observed after 10 months. Marked cytological atypia of bizarre cells in PA, even when involving ductal cells, may not necessarily indicate malignancy. This case highlights the value of integrating clinicopathological and genetic findings to better define PAs with bizarre cells and prevent overdiagnosis of carcinoma based on atypia alone.
Splenic hamartomas are rare, benign nodular lesions composed of disorganized, sinusoid-like vascular structures within the splenic parenchyma. Occasionally, these lesions may harbor scattered bizarre stromal cells. A 47-year-old female presented with epigastric pain. Imaging (US and CT) revealed a complex cystic lesion in the midline of the spleen. Histological examination showed irregular vascular channels lacking white pulp, interspersed with solitary bizarre stromal cells featuring vesicular chromatin and scant cytoplasm. No mitotic activity or infiltrative growth was identified. Immunohistochemically, the vascular components were CD31, CD34, and CD8 positive. The bizarre stromal cells expressed vimentin, WT-1, cyclin D1, and OCT-4, while remaining negative for Ki-67. A diagnosis of splenic hamartoma with bizarre stromal cells was rendered. Splenic hamartoma with bizarre stromal cells is exceedingly rare, with only seven cases previously reported in the English literature. These atypical cells can mimic malignancy, posing a diagnostic challenge. We report this case to highlight these diagnostic pitfalls alongside a literature review.
Myolipoma is a rare benign mesenchymal tumor composed of mature adipose tissue, smooth muscle bundles and blood vessels, which predominantly occurs in the retroperitoneum, inguinal region and abdominal wall. Primary uterine involvement is extremely uncommon, and the presence of bizarre-nucleated cells within such tumors is even rarer. The morphological features of these cells may mimic malignant neoplasms, posing great challenges for clinical and pathological diagnosis. We report a 61-year-old female patient with imaging and ultrasonographic findings suggestive of a uterine space-occupying lesion. Histopathological examination and immunohistochemical staining were performed on the surgically resected specimen, with the detected markers including smooth muscle actin (SMA), Desmin, HMB45, Melan A, S-100 and Ki-67. Pelvic magnetic resonance imaging (MRI) revealed a well-demarcated heterogeneous signal mass in the anterior wall of the uterine corpus, consistent with the manifestations of a benign tumor containing adipose components. Gross examination showed a well-circumscribed intramural mass of the uterus with a grayish-yellow and heterogeneous cut surface. Microscopically, mature adipocytes and benign smooth muscle cells were scattered with bizarre-nucleated cells characterized by markedly enlarged and irregular nuclei; no mitotic figures or necrotic foci were identified. Immunohistochemically, the smooth muscle component showed diffuse and strong positivity for SMA and Desmin, while HMB45, Melan A and S-100 were all negative. The Ki-67 proliferation index was extremely low (<1%), confirming the diagnosis of uterine myolipoma with bizarre-nucleated cells. Uterine myolipoma with bizarre-nucleated cells is an exceedingly rare benign tumor, and no recurrence or metastasis was observed during postoperative follow-up, indicating its indolent biological behavior. Accurate diagnosis requires the combination of imaging features, adequate sampling, meticulous histological evaluation and targeted immunohistochemical detection to distinguish it from leiomyosarcoma, liposarcoma and perivascular epithelioid cell tumor (PEComa).
Self-injurious behavior (SIB) is common in prisons, but a small subset of episodes involves extreme medical severity, atypical methods, and striking psychiatric complexity. This retrospective mixed-methods study aimed to identify and describe "extreme" SIB within a large U.S. state prison system and to characterize its medical, behavioral, and contextual features. We reviewed 5.5 years of critical incident reports and, from all self-harm-related events, identified 85 episodes that met an a priori definition of extreme SIB, including clear risk of death or disfigurement, ingestion or insertion of foreign bodies or toxic substances, targeting of the face, eyes, or genitals, bizarre or psychotic features, and/or use of multiple severe methods in a single episode. Quantitative coding documented that most incidents (80%) involved life-threatening medical risk, nearly half (49%) featured ingestion or insertion of foreign objects or toxic substances, over one third (35%) targeted the face, eyes, or genitals, and 41% combined more than one severe method; altered mental states or bizarre behavior were described in 59% of events. Thematic analysis of staff narratives highlighted massive blood loss, unusual instruments and body insertion, symbolic attacks on identity and sexuality, "method stacking," and altered mental states, often in the context of segregation, disciplinary action, or adverse legal news. Extreme SIB appears to be a low base-rate but high-impact phenomenon that concentrates psychiatric morbidity, medical cost, and institutional disruption, and is often poorly matched to standard custodial responses. The findings support the need for specialized forensic assessment, clinical management, and policy responses for this subgroup.
Bizarre parosteal osteochondromatous proliferation (BPOP), or Nora's lesion, is a rare benign surface bone lesion typically arising in the hands and feet. We report an unusual case involving the temporal bone in a 63-year-old woman, presenting with progressive external auditory canal obstruction and hearing-related symptoms. Imaging revealed a well-circumscribed osseous mass without corticomedullary continuity, and surgical excision with canaloplasty led to complete symptom resolution. This case expands the recognized anatomical spectrum of Bizarre parosteal osteochondromatous proliferation (BPOP) and underscores the importance of including it in the differential diagnosis of surface bone lesions in the craniofacial region, where even benign processes may result in significant functional impairment due to local anatomy.
Bizarre parosteal osteochondromatous proliferation (BPOP), or Nora lesion, is a rare benign condition that can mimic other pathologies. A case is described of a 66-year-old man with a slowly enlarging nodule on his finger over five years. Imaging showed a parosteal lesion without continuity with the trabecular bone, strongly suggestive of BPOP. The diagnosis was histologically confirmed. This case highlights the importance of recognizing the characteristic imaging features of BPOP. Teaching point: BPOP may appear as a worrisome lesion on imaging, but its typical location and lack of continuity with the trabecular bone should raise awareness for BPOP.
Bizarre parosteal osteochondromatous proliferation (BPOP), also known as Nora's lesion, is a rare, benign bone tumor predominantly affecting the small bones of the hands and feet. It presents as a diagnostic challenge due to its radiologic and histologic resemblance to malignant bone lesions, such as osteosarcoma and parosteal chondrosarcoma. This case series describes the clinical presentation, imaging features, surgical management, and post-operative outcomes of three patients with BPOP involving the small bones of the hand. Radiological imaging, including magnetic resonance imaging and computed tomography scans, played a crucial role in identifying periosteal-based lesions with cortical involvement. Histopathological examination confirmed the diagnosis, distinguishing it from more aggressive conditions. Surgical excision with wide margins was the primary treatment and resulted in favorable outcomes without evidence of recurrence during follow-up. Despite its benign nature, BPOP has a high recurrence rate, emphasizing the importance of long-term monitoring. This series contributes to the growing literature on BPOP, highlighting the need for accurate diagnosis and appropriate surgical techniques. Future research into the genetic background of BPOP may provide further insights into its pathogenesis and its recurrence, potentially guiding more effective management strategies.
Bizarre parosteal osteochondromatous proliferation (BPOP), or Nora's lesion, is a rare benign bone tumour that most commonly affects the bones of the hands and feet. It presents diagnostic challenges due to its aggressive imaging features, high recurrence rate and histological overlap with malignant lesions. We report the case of an adolescent girl who presented with a hard, ulcerated swelling over the distal phalanx of the right great toe. Imaging revealed corticomedullary continuity of the lesion with the underlying phalanx, raising suspicion for osteochondroma or subungual exostosis. Surgical excision was performed, and histopathology confirmed BPOP, showing binucleated chondrocytes, endochondral ossification and the characteristic 'blue bone'. No recurrence was observed during a 1-year follow-up period. This case highlights the importance of considering BPOP in the differential diagnosis of toe lesions particularly when atypical radiological features are present. Histopathological examination remains the cornerstone for definitive diagnosis.
Bizarre parosteal osteochondromatous proliferation (BPOP) is a rare benign lesion, first described by Nora et al. in 1983, that typically affects the small bones of the hands and feet. We report a rare case of BPOP arising from the left second rib in a 41-year-old man, which was incidentally detected as a "pulmonary mass" on the chest X-ray during a routine health checkup. CT imaging revealed a lesion measuring 4.1 × 2.2 cm in size in the second left rib, and we performed surgical resection for both diagnosis and treatment. Postoperative histopathological examination revealed the diagnosis of BPOP. This case underscores the importance of including BPOP in the differential diagnosis of rib lesions, especially when the imaging findings suggest a benign osteocartilaginous lesion. Given the potential of the lesion for recurrence, long-term follow-up of persons with BPOP is recommended.
Bizarre parosteal osteochondromatous proliferation (BPOP), or Nora's lesion, is an unusual, benign, parosteal lesion comprising bone, fibrous tissue, and cartilage. Clinically, the lesions present as slowly growing hard protuberances that are painless in most cases unless they cause local symptoms due to mass effect, including pain, palpable mass, and functional impairment. Surgical resection is indicated when lesions imply pain and functional limitations, aiming at alleviating symptoms and achieving definitive pathological diagnosis in doubtful cases. The purpose of this technical note is to report the details of endoscopic resection of BPOP of the calcaneocuboid joint. This minimally invasive approach minimizes the potential surgical morbidity associated with wide resection.
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Bizarre parosteal osteochondromatous proliferation (BPOP), or Nora's lesion, is a benign but locally aggressive osteochondroid proliferation that almost exclusively involves the small bones of the hands and feet. Spinal involvement is exceptionally rare, with only two cases previously reported. We describe a 13-year-old boy who presented with progressive lower-limb weakness, gait instability, urinary urgency, and significant weight loss. MRI demonstrated a well-circumscribed intradural extramedullary mass at L1 with mixed signal characteristics and peripheral enhancement, initially raising concern for neoplastic or vascular pathology. Surgical resection via L1 laminotomy revealed a firm, partially mineralized lesion densely adherent to several nerve roots. Histopathologic examination showed hypercellular cartilage, immature "blue bone," and reactive osteoblastic rimming, establishing the diagnosis of BPOP. Postoperative recovery demonstrated partial neurological improvement. This case represents the third reported spinal BPOP and the first pediatric case. Its highly unusual intradural location and deceptive imaging appearance highlight the importance of considering BPOP in the differential diagnosis of mineralized intradural masses. Early recognition is critical to avoid overtreatment and to guide long-term surveillance given the lesion's propensity for recurrence.
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Caudal vertebrae of caenophidian snakes are characterized by the presence of paired haemapophyses-a pattern observed from the earliest-diverging acrochordid lineage to the most derived viperids, and documented in the fossil record from the Late Cretaceous onward, including the basalmost known extinct caenophidian forms. Using micro-computed tomography scanning, we document an extraordinary deviation from this pattern. We examined five species across three genera of the Asian family Calamariidae (Reed snakes) and demonstrate that they, uniquely among Colubroidea, lack haemapophyses throughout the caudal vertebral series, possessing instead prominent haemal keels-a condition that represents a novel diagnostic feature for Calamariidae. This simplification of vertebral morphology, coupled with an extremely reduced number of caudal vertebrae, likely correlates with the fossorial lifestyle characteristic of this snake family. Furthermore, we identify and illustrate unexpected modifications of subcentral structures in certain other caenophidian taxa, that is, a pareid and several distantly related elapoid species. Our findings underscore the significant taxonomic and diagnostic value of caudal vertebral morphology, a skeletal element that has been largely overlooked.
In this study of mutual gaze (MG) and emotion, using multiple groups of chimpanzee infants to compare with multiple groups of human infants, we provide a methodology to assess two deeply rooted assumptions: (1) Psychological outcomes in chimpanzees are uninfluenced by socioecological conditions, and (2) samples from humans living in Western, middle-class family settings are adequate representatives of humankind. Even though MG is widely viewed as foundational for social cognition, and gaze becomes coordinated with emotion around 1 year of age, these topics have rarely been studied in 1-year-old chimpanzees. We studied four diverse chimpanzee groups-that is, 1-year-old infants living at Chester Zoo (n = 4), in Gombe National Park (n = 12), at the Primate Research Institute (n = 3), and in a human home (n = 2)-and compared them with three diverse groups of human 1-year-olds: urban-UK (n = 8), subsistence farming-Nso (n = 12), and foraging-Aka (n = 10). MG occurred 22% of the time and did not differ across groups or species. We found no species differences in any infant Emotion or in any MG-Emotion co-occurrence pattern. In three of five types of MG-Emotion co-occurrence, the Primate Research Institute chimpanzee infants differed from at least one of the other chimpanzee groups (we reject Assumption 1), and the UK infants differed from at least one of the other human groups (we reject Assumption 2). We conclude there are meaningful influences of socioecology on the functions of some social cognition outcomes, and, thus, it is necessary to sample multiple diverse groups to detect true species differences. (PsycInfo Database Record (c) 2026 APA, all rights reserved).
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Hawking's signature prediction may prevent vexing singularities from forming.
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