Chronic Administration of Recombinant Human Erythropoietin Induces Angiogenesis in Healthy Mouse Brain.

Introduction The hematopoietic growth factor erythropoietin (EPO) plays an important role in apoptosis and oxidative stress attenuation as well as the promotion of angiogenesis in several tissues. Systemically administered EPO has beneficial effects on rabbits subjected to subarachnoid hemorrhage or stroke. So far, the angiogenic effect of EPO has been documented after an experimentally induced stroke or subarachnoid hemorrhage. In our study, we examined the possible angiogenic effect of chronic treatment with recombinant human erythropoietin (rHuEPO) under normal conditions, in an attempt to clarify if the existence of a lesion or oxygen deprivation is necessary to initiate the angiogenic effect of EPO. Materials & methods BALB/c mice were used and were divided into three groups as follows: group A (no treatment), group B (saline only), and group C (7000 U rHuEPO per week for three weeks by intraperitoneal injection). The number of CD31- and CD34-positive endothelial cells was assessed in mouse brain preparations under control conditions and after treatment with rHuEPO. Results There was no difference between the mean numbers of CD31 and CD34 cells among the different groups. The mean number of vessels in group A and group B was almost the same (18 ± 2 vessels per optical field). However, the number of brain vessels in group C (EPO treatment) increased significantly by 44% compared to controls (26 ± 4 vessels per optical field, P < 0.05). Conclusion These data indicate that no lesion or oxygen deprivation is needed to initiate the angiogenic effect of EPO in healthy mouse brains.

Mucinous Carcinoma of the Breast With Neuroendocrine Differentiation: A Case Report of Cyto-Histopathology Findings.

Mucinous breast carcinoma is a rare neoplasm. A minority of breast neoplasms exhibit a mucinous component, with purely mucinous cases being less frequent. It is more typically found in postmenopausal women. The etiology is multifactorial and involves dietary factors, reproductive factors, and hormonal factors. Mucinous carcinoma can grow to a large size at the time of diagnosis, although it typically grows slowly and palpable. Transcriptomic genetic studies have explained that mucinous tumors are of luminal A molecular subtype. Mucinous A tumors have different transcriptome characteristics than mucinous B tumors, which have a gene expression pattern resembling neuroendocrine (NE) carcinomas. Diagnosis of mucinous carcinoma with NE differentiation by fine needle aspiration cytology (FNAC) is reported infrequently. Histopathology is mandatory in the evaluation of mucinous breast carcinoma. NE carcinoma of the breast is an underestimated subtype of BC which has characteristics of heterogenicity, rarity, and poor differentiation. In this instance, we present a case of breast carcinoma exhibiting NE differentiation. A postmenopausal woman aged 63, with no family history of breast cancer, presented with a firm mass in the upper lateral quadrant of her right breast. This lump, causing discomfort for the past two years, was accompanied by nipple retraction and the discharge of bloody fluid. The clinical examination revealed the palpable presence of the lump. Ultrasonography-guided FNAC suggested Mucinous breast carcinoma with NE differentiation. The patient underwent a modified radical mastectomy, and the tissue was evaluated by immunohistochemistry which confirmed the diagnosis.

Metaplastic Breast Carcinoma: A Rare Presentation in a Young Female With Double Hormone Receptor-Positive Tumor.

Metaplastic breast carcinoma (MBC) represents a rare subtype of breast cancer, characterized by poor prognostic indicators that have been recently identified. Clinical and radiological presentations often mimic other breast cancer types, necessitating immunohistochemistry (IHC) for accurate diagnosis. In this study, we report a case involving a 31-year-old female presenting with a painless, fixed, non-inflammatory mass in the left breast, which was confirmed as MBC. Treatment encompassed lumpectomy, chemotherapy, radiotherapy, and subsequent hormonal therapy. Understanding this rarely reported yet aggressive form of breast cancer holds significant importance for clinicians, enabling them to promptly establish a diagnosis and implement effective management strategies.

Adnexal Clear Cell Carcinoma Exhibiting Comedonecrosis of the Ear: A Rare Case Treated With Mohs Micrographic Surgery.

Adnexal clear cell carcinoma exhibiting comedonecrosis (ACCCC) is a rare, cutaneous, malignant neoplasm with limited reported cases since its discovery. ACCCC is characterized by unique clinical and histological features, demanding a precise diagnosis due to its potential for aggressive behavior and early metastases, distinct from other cutaneous tumors with clear cytoplasmic cells. We present the case of an 81-year-old male with a history of multiple non-melanoma skin cancers, who presented with a 5 mm erythematous papule on his left tragus. Initial tangential shave biopsy results were invasive clear cell squamous cell carcinoma that was moderately differentiated. Subsequent Mohs micrographic surgery (MMS) necessitating a full-thickness skin graft reconstruction was performed. Histopathological examination afterward confirmed ACCCC with pleomorphic epithelial cells, clear cytoplasm, and central comedonecrosis. Immunohistochemistry supported adnexal differentiation and squamous features. To our knowledge, this is the fifteenth reported case of ACCCC as well as the first documented case of ACCCC treated with MMS, offering a novel approach to managing this rare malignancy.

Diagnostic Maze: Malignant Phyllodes Tumor Mimicking Metaplastic Breast Carcinoma.

Phyllodes tumors (PTs) are uncommon breast tumors. They represent a spectrum of benign to malignant neoplasms. These erratic tumors have traits ranging from fibroadenomas on one end of the spectrum to sarcomas on the other end. The presentation of PT is variable, thus posing a diagnostic difficulty. Malignant PTs are often associated with recurrence, poor prognosis, and adverse disease outcomes. The recent genetic studies produced by genome sequencing offer information about the molecular pathophysiology of PT, aid in enhancing diagnostic precision, and suggest possible therapeutic targets in cases of malignant PT. Planning a treatment modality and prognostication requires meticulous histopathological sampling, as it relies on a correct histopathological diagnosis. There are no definitive guidelines for surgical management and targeted therapy for malignant PTs due to the rarity of these cases and very little available literature on these topics. Here in this article, we address a malignant PT in a 74-year-old female that presented as a breast mass mimicking metaplastic breast carcinoma histologically. This article also illuminates how immunohistochemistry plays a vital role in the diagnosis of this tumor.

Spatial distribution pattern of immune cells is associated with patient prognosis in colorectal cancer.

BACKGROUND: The spatial context of tumor-infiltrating immune cells (TIICs) is important in predicting colorectal cancer (CRC) patients' clinical outcomes. However, the prognostic value of the TIIC spatial distribution is unknown. Thus, we aimed to investigate the association between TIICs in situ and patient prognosis in a large CRC sample. METHODS: We implemented multiplex immunohistochemistry staining technology in 190 CRC samples to quantify 14 TIIC subgroups in situ. To delineate the spatial relationship of TIICs to tumor cells, tissue slides were segmented into tumor cell and microenvironment compartments based on image recognition technology, and the distance between immune and tumor cells was calculated by implementing the computational pipeline phenoptr. RESULTS: MPO+ neutrophils and CD68+IDO1+ tumor-associated macrophages (TAMs) were enriched in the epithelial compartment, and myeloid lineage cells were located nearest to tumor cells. Except for CD68+CD163+ TAMs, other cells were all positively associated with favorable prognosis. The prognostic predictive power of TIICs was highly related to their distance to tumor cells. Unsupervised clustering analysis divided colorectal cancer into three subtypes with distinct prognostic outcomes, and correlation analysis revealed the synergy among B cells, CD68+IDO1+TAMs, and T lineage cells in producing an effective immune response. CONCLUSIONS: Our study suggests that the integration of spatial localization with TIIC abundance is important for comprehensive prognostic assessment.

Deep learning-based hyperspectral technique identifies metastatic lymph nodes in oral squamous cell carcinoma-A pilot study.

AIMS: To establish a system based on hyperspectral imaging and deep learning for the detection of cancer cells in metastatic lymph nodes. MAIN METHODS: The continuous sections of metastatic lymph nodes from 45 oral squamous cell carcinoma (OSCC) patients were collected. An improved ResUNet algorithm was established for deep learning to analyze the spectral curve differences between cancer cells and lymphocytes, and that between tumor tissue and normal tissue. KEY FINDINGS: It was found that cancer cells, lymphocytes, and erythrocytes in the metastatic lymph nodes could be distinguished basing hyperspectral image, with overall accuracy (OA) as 87.30% and average accuracy (AA) as 85.46%. Cancerous area could be recognized by hyperspectral image and deep learning, and the average intersection over union (IOU) and accuracy were 0.6253 and 0.7692, respectively. SIGNIFICANCE: This study indicated that deep learning-based hyperspectral techniques can identify tumor tissue in OSCC metastatic lymph nodes, achieving high accuracy of pathological diagnosis, high work efficiency, and reducing work burden. But these are preliminary results limited to a small sample.

Erythroblastosis Transformation-Specific Regulated Gene 1 (ERG) Immunohistochemistry in the Diagnosis of Acute Myeloid Leukemia.

INTRODUCTION: The erythroblastosis transformation-specific regulated gene 1 (ERG) is a transcription factor that can be used as an immunohistochemical (IHC) marker in the diagnosis and prognostication of malignancy. ERG was initially used in prostate cancer; however, it is a useful marker in extramedullary myeloid disease. Patients with acute myeloid leukemia (AML), dry bone marrow aspirate, and CD34, CD117-negative blast cells can be in a diagnostic dilemma. This audit aimed to (a) validate ERG IHC in bone marrow trephine samples, (b) quantify ERG IHC positivity in an AML cohort, and correlate concordance with CD34 and CD117 IHC, when available, and (c) to see whether ERG is a useful adjunct in the diagnosis of cases of AML. METHODS: A retrospective audit was completed of all new and relapsed cases of AML over one year at a single center. For inclusion, patients needed a trephine specimen at presentation, and all had a hematoxylin and eosin(H&E) specimen, ERG IHC, and at least one or both of CD34 and CD117 IHC. Four pathologists independently assessed the stains quantitatively and qualitatively in comparison to the morphology seen on the H&E sample. The kappa value was used to assess agreement. RESULTS: Seventeen patients with AML met the inclusion criteria. All specimens had H&E, CD34, and ERG stains; 9/17 (53%) had CD117 IHC. ERG demonstrated high concordance with blast cells on H&E morphology, with a high agreement among pathologists. Qualitatively, pathologists recognized that ERG spared lymphoid nodules; however, it also stained granulocytes at various maturation stages. CONCLUSION: ERG is a sensitive marker for the diagnosis of AML. ERG can help visualize blast cells that have been confirmed by ancillary tests. More research into the utility of ERG in AML diagnostics is recommended.

Dual Malignancies Discovered: A Rare Case of Malignant Peritoneal Epithelioid Mesothelioma and Lung Adenocarcinoma.

Clinicians diagnosing malignant peritoneal epithelioid mesothelioma (MPM or MPeM) have historically had challenges due to the low incidence of the disease, as well as the often vague symptomatology that patients present with. Newer advances in technology, specifically in immunocytochemistry, have provided a clearer path to diagnosis. Additionally, malignant mesotheliomas must be differentiated from carcinomas. This is done via histology, immunocytochemistry, as well as a careful incorporation of the patient's clinical history. In this case, we present an asymptomatic 73-year-old non-smoker female with no past medical history of asbestos exposure. She was diagnosed with MPM following a routine abdominal hernia repair. Subsequent workup revealed a lung infiltrate that was successfully biopsied and resected, evidently found to be adenocarcinoma. A careful review of the resulting pathology, as well as the interpretation of immunocytochemistry, supported the notion that the patient had two independent malignant processes occurring at once. This case underscores the rarity of two similar, yet distinct cancers, as well as epidemiology, symptomatology, histology, immunocytochemistry, and prognosis.

Malignant Ileocolocolic Intussusception in a 19-Year-Old Male.

Adult intussusception is an infrequent occurrence typically resulting from an identifiable lead point of a benign or malignant etiology. Here, we present a case of a 19-year-old male who presented to the emergency department with complaints of abdominal pain, intractable nausea, and fluctuations between bloody diarrhea and constipation. These symptoms had begun two months prior and had increased in severity, resulting in significant appetite changes. An abdominal and pelvic computed tomography scan without contrast was obtained, which showed evidence of intussusception of the ileocecum into the transverse colon with resultant small bowel obstruction. The patient underwent an exploratory laparotomy, which resulted in a partial ileocolectomy due to the presence of a 6.8 cm cecal mass with palpable mesenteric lymphadenopathy. The pathologic specimen was identified as Burkitt lymphoma based on a combination of histologic, immunohistochemical, and fluorescence in situ hybridization findings. Currently, the patient is undergoing three cycles of rituximab, cyclophosphamide, vincristine, doxorubicin, high-dose methotrexate, ifosfamide, etoposide, and high-dose cytarabine (R-CODOX-M/IVAC) per Magrath protocol for low-risk Burkitt lymphoma.

Neck Epithelioid Sarcoma at an Unusual Location Mimicking Lymph Node Metastases of Nasopharyngeal Carcinoma: A Case Report.

Epithelioid sarcoma (ES) is an uncommon soft tissue sarcoma. It is usually located in the extremities and exceptionally in the neck. Its diagnosis constitutes a real challenge which is based on histology and immunohistochemistry staining that must be interpreted with caution given the anatomopathological similarities to other tumors. In this article, we report a case of a 37-year-old man admitted for a locally advanced ES of the neck. There were suspicions of lymph node metastases of nasopharyngeal carcinoma at the first pathological examination. The patient received palliative chemotherapy and was referred to the supportive care department. Through this case, we will discuss the clinical and anatomopathological characteristics and therapeutic options of this extremely rare tumor which poses a diagnostic challenge.

Role of Geminin as a Tool for Augmenting Accurate Diagnosis of Cervical Neoplasia.

AIM: To determine the role of geminin as a tool for differentiating various types of cervical intraepithelial neoplasia (CIN) and cervical carcinoma (CC). METHODS: Seventy women newly diagnosed with CIN or CC undergoing cervical biopsy were included; their clinical profile, human papilloma virus (HPV) positivity, and colposcopy findings were noted, and biopsy tissue was analyzed for geminin content. RESULTS: On geminin immunohistochemistry, 100% of women with CIN3 and 96.29% of women with CC had geminin two plus or more. When analyzed as ordinal variables, there was a significant correlation (spearman's rho 0.35, p 0.01) between geminin and biopsy results (CIN1, CIN2, CIN3, and CC). CONCLUSIONS: Screening tests for cervical cancer, like conventional pap smears, liquid-based pap smears, and triaging with HPV, have limitations. It is important to be able to differentiate between high-grade lesions, invasive cancer, and low-grade lesions. The detection of geminin in these cells may aid in the confirmation of the diagnosis and ensure adequate treatment. Cervical intraepithelial lesions and carcinoma cervix demonstrated a correlation between increased geminin expression in CIN1 vs. CC and CIN2 vs. CC. Geminin may be a potential surrogate marker for higher-grade cervical lesions, and further research is needed to corroborate evidence in this direction.

Recurrent Gastrointestinal Stromal Tumor With Chondroid Differentiation After Imatinib Therapy: An Unusual Case and Literature Review.

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor in the gastrointestinal tract and is most commonly seen in the stomach. The standard treatment for patients with advanced GISTs include both surgical resection and imatinib therapy. There have been cases that document the alterations of patients' GIST histomorphology both with primary GIST prior to imatinib therapy and with recurrent GIST after imatinib therapy. However, there has been no documented case of a patient who has recurrent GIST with chondroid differentiation at the primary site after imatinib therapy. In this article, we report an incidental finding of a 58-year-old patient who had two treatments of imatinib therapy prior to surgical resection of her recurrent GIST in her stomach. We also explore through a mini-literature review the various cases of GIST with chondroid differentiation that have been reported to compare the histomorphology, immunophenotype, and patient demographic of these cases. This article is significant for reporting a rare finding of GIST after imatinib therapy and highlights the various presentations that GIST could acquire after imatinib therapy that exclude another malignant process, such as chondrosarcoma.

Low-Powered View, High-Powered Mind: A Case Report of Morpheaform Basal Cell Carcinoma Mistaken for Metastatic Breast Carcinoma.

Basal cell carcinoma (BCC) is one of the most common skin malignancies worldwide. Morpheaform basal cell carcinoma (MBCC) is a rare aggressive subtype of BCC that presents with unique histologic features. Both are treated surgically and have an excellent survival rate. Metastatic breast carcinoma, on the other hand, has a poor survival rate along with a more burdensome therapeutic route including chemotherapy. Due to an overlap in common immunohistochemistry stains, there is a possibility of confusing the diagnosis of BCC with metastatic breast carcinoma resulting in potential patient harm. Therefore, a timely and accurate diagnosis distinguishing these malignancies is essential. We report a near-miss event in which a 77-year-old female with MBCC was mistakenly diagnosed with metastatic breast carcinoma. We discuss the details of these stains, characteristic features of MBCC, and treatment options and emphasize the importance of combining laboratory medicine with clinical expertise to improve patient outcomes.

A Preliminary Study of the Role of Endothelial-Mesenchymal Transitory Factor SOX 2 and CD147 in the Microvascularization of Oral Squamous Cell Carcinoma.

INTRODUCTION: The aim of this study was to detect the possible endothelial expression of embryonic-type cancer stem cells (CSC) marker SOX2 and the stemness-type CSC marker CD147 in oral potential malignant disorders (OPMDs), oral leukoplakia (OL) in particular, and oral squamous cell carcinoma (OSCC). METHODS: This study focuses on the immunohistochemical pattern of expression of CSC protein-biomarkers SOX2 and CD147 in paraffin-embedded samples of 21 OSCCs of different grades of differentiation and 30 cases of OLs with different grades of dysplasia, compared to normal oral mucosa. RESULTS: The protein biomarker SOX2 was expressed in the endothelial cells, but without establishing any statistically significant correlation among OSCC, OL, and normal tissue specimens. However, SOX endothelial staining was noticed in 7/30 (23.3%) cases of OL (one non-dysplastic, one mildly dysplastic, one moderately dysplastic, and four severely dysplastic cases) and 5/21 (23.8%) cases of OSCC (two well-differentiated, one moderately differentiated, and two poorly differentiated cases). Although CD147 is expressed in normal oral epithelium, OL, and OSCC neoplastic cells, its vascular-endothelial expression was noticed in only 2/5 (40%) cases of normal oral epithelium, 1/30 (3.3%) cases of OL (one severely dysplastic case), and 4/21 (19%) cases of OSCC (two well-differentiated, one moderately differentiated, and one poorly differentiated case). Therefore, no statistically significant correlation among OSCC, OL, and normal tissue specimens was established. CONCLUSION: The endothelial presence of SOX2 both in oral potentially malignant and malignant lesions suggests that SOX2 may be implicated in the microvascularization process and associated with the degree of dysplasia in OL. The expression of CD147 may be attributed both to local inflammation and tumorigenesis. The implementation of CD147 in larger groups of tissue samples will shed some light on its role in cancer and inflammation. The evidence so far supports the need for more studies, which may support the clinical significance of these novel cancer stem cell biomarkers.

Globo H ceramide is an independent prognostic marker for gallbladder cancer.

In recent studies, there has been growing interest in developing cancer therapeutics targeting Globo H ceramide, which is considered as the most prevalent tumor-associated carbohydrate antigen in epithelial cancers. In this study, we aimed to evaluate the expression of Globo H and investigate its prognostic significance in gallbladder cancer (GBC). The tumor specimens and clinical characteristics of GBC patients were collected from the tumor bank and database of Chang Gung Memorial Hospital. Globo H in tumor specimens was detected by immunohistochemistry (IHC) and mass spectrometry analysis. Through data mining, it was discovered that FUT1 and FUT2, which are key enzymes involved in the biosynthesis of Globo H, were significantly up-regulated in human gallbladder cancer (GBC). Consistent with this finding, Globo H expression was detected in 86% (128 out of 149) of GBC specimens using immunohistochemical (IHC) staining. This was the highest frequency among Globo H expressing cancers. Patients with tumors exhibiting higher Globo H expression (H-score ≥ 80) demonstrated significantly shorter disease-free survival (DFS) and overall survival (OS) (P = 0.0001 and P = 0.0004, respectively). In a multivariable Cox regression analysis, elevated Globo H expression was identified as an independent unfavorable predictor for DFS and OS (hazard ratio: 2.29 and 2.32, respectively, P = 0.008 and 0.001) in primary GBC. Globo H is an independent prognostic marker for GBC.

An orientation-free ring feature descriptor with stain-variability normalization for pathology image matching.

Comprehensively analyzing the corresponding regions in the images of serial slices stained using different methods is a common but important operation in pathological diagnosis. To help increase the efficiency of the analysis, various image registration methods are proposed to match the corresponding regions in different images, but their performance is highly influenced by the rotations, deformations, and variations of staining between the serial pathology images. In this work, we propose an orientation-free ring feature descriptor with stain-variability normalization for pathology image matching. Specifically, we normalize image staining to similar levels to minimize the impact of staining differences on pathology image matching. To overcome the rotation and deformation issues, we propose a rotation-invariance orientation-free ring feature descriptor that generates novel adaptive bins from ring features to build feature vectors. We measure the Euclidean distance of the feature vectors to evaluate keypoint similarity to achieve pathology image matching. A total of 46 pairs of clinical pathology images in hematoxylin-eosin and immunohistochemistry straining to verify the performance of our method. Experimental results indicate that our method meets the pathology image matching accuracy requirements (error ¡ 300µm), especially competent for large-angle rotation cases common in clinical practice.

Risk-stratification machine learning model using demographic factors, gynaecological symptoms and ß-catenin for endometrial hyperplasia and carcinoma: a cross-sectional study.

BACKGROUND: Demographic features, suggestive gynaecological symptoms, and immunohistochemical expression of endometrial ß-catenin have a prognostic capacity for endometrial hyperplasia and carcinoma. This study assessed the interaction of all variables and developed risk stratification for endometrial hyperplasia and carcinoma. METHODS: This cross-sectional study was conducted from January 2023 to July 2023 at two teaching hospitals in Makassar Indonesia. Patients (< 70 years old) with suggestive symptoms of endometrial hyperplasia or carcinoma or being referred with disease code N.85 who underwent curettage and/or surgery for pathology assessment except those receiving radiotherapy, or chemotherapy, presence of another carcinoma, coagulation disorder, and history of anti-inflammatory drug use and unreadable samples. Demographic, and clinical symptoms were collected from medical records. Immunohistochemistry staining using mouse-monoclonal antibodies determined the ß-catenin expression (percentage, intensity, and H-score) in endometrial tissues. Ordinal and Binary Logistic regression identified the potential predictors to be included in neural networks and decision tree models of histopathological grading according to the World Health Organization/WHO grading classification. RESULTS: Abdominal enlargement was associated with worse pathological grading (adjusted odds ratio/aOR 6.7 95% CI 1.8-24.8). Increasing age (aOR 1.1 95% CI 1.03-1.2) and uterus bleeding (aOR 5.3 95% CI 1.3-21.6) were associated with carcinoma but not with %ß-catenin and H-Score. However, adjusted by vaginal bleeding and body mass index, lower %ß-catenin (aOR 1.03 95% 1.01-1.05) was associated with non-atypical hyperplasia, as well as H-Score (aOR 1.01 95% CI 1.01-1.02). Neural networks and Decision tree risk stratification showed a sensitivity of 80-94.8% and a specificity of 40.6-60% in differentiating non-atypical from atypical and carcinoma. A cutoff of 55% ß-catenin area and H-Score of 110, along with other predictors could distinguish non-atypical samples from atypical and carcinoma. CONCLUSION: Risk stratification based on demographics, clinical symptoms, and ß-catenin possesses a good performance in differentiating non-atypical hyperplasia with later stages.

Lymphoepithelial Carcinoma of the Breast.

Lymphoepithelial malignancy is an extremely rare carcinoma of the breast characterized by a confusing histopathological picture resembling medullary carcinomas, lymphoma, etc. It has also been reported in other regions of the body like salivary glands, nasopharyngeal area and sometimes the lung. Due to its rare presence and difficult diagnosis, the treatment is often prolonged and delayed. Here we present a case report of a 56-year-old lady who was eventually diagnosed as lymphoepithelial carcinoma of the breast. Her journey of evaluation and treatment was fraught with pathological nuances and an elimination drill of multiple differentials before concluding this rare diagnosis. Although lymphoepithelial-like carcinoma is a rare entity, multiple cases have been reported in the literature and their review is mandated to further our clinical knowledge about the oncological treatment and expected prognosis of such cases in the future. Our patient underwent a simple mastectomy, followed by chemotherapy, radiotherapy, and is completely asymptomatic now. She has been cancer-free for the last seven years so far.

Male pseudohermaphroditism in a complex malformed calf born with an acardius amorphus cotwin-a case report.

BACKGROUND: Male pseudohermaphroditism is a developmental anomaly wherein animals are genetically and gonadally male, but their internal and/or external genitalia resemble those of females. In cattle, pseudohermaphroditism is often accompanied by multiple severe malformations. To the best of our knowledge, this is the first report of male pseudohermaphroditism in a complex malformed calf born with an acardius amorphous cotwin. CASE PRESENTATION: This report describes the case of a three-day-old, male anurous Japanese Black calf born with an acardius amorphous cotwin, complete absence of the tail, agenesis of the anus, separate scrota, and umbilical hernia. Transthoracic echocardiography and computed tomography revealed serious malformations in the skeletal system and the circulatory, digestive, urinary, and genital organs. Necropsy revealed rectal atresia, immature testes, epididymis, and penis, but no male accessory gonads. Histological analyses revealed vaginal- and uterine-like tissues adjacent to or fused to the rectum. Fluorescence in situ hybridization detected X and Y chromosomes, and some cells presented two X-probe signals in the same nucleus. CONCLUSIONS: In contrast to the male genitalia, the female genitalia derived from the Müllerian ducts were difficult to detect by necropsy in the presented case. Many similar cases may be overlooked in clinical practice.