International Journal of Surgical Pathology

Myofibroblastoma is a rare benign mesenchymal tumor first described in the breast. It is also known as mammary-type myofibroblastoma outside of the breast, more frequently located along the embryonic milk line. Exceptionally, myofibroblastoma can occur at visceral locations. We present a case of myofibroblastoma detected incidentally in the liver. A well-circumscribed mass, grossly measuring 6.2 cm in the liver parenchyma, was found on imaging studies. Histologically, the lesion is characterized by benign spindle cells in a hyalinized collagenous stroma, with positive staining for SMA and ER, focal positivity for CD34, negative for desmin, and loss of RB1...

Introduction: Molecular analysis plays a growing role in the diagnosis of mesenchymal neoplasms. The aim of this study was to retrospectively apply broad, multiplex molecular assays (a solid tumor targeted next-generation sequencing [NGS]) assay and single nucleotide polymorphism [SNP] microarray) to selected tumors, exploring the current utility and limitations. Methods: We searched our database (2010-2020) for diagnostically challenging mesenchymal neoplasms. After histologic review of available slides, tissue blocks were selected for NGS, SNP microarray, or both...

The last decade has seen great advances in genomic profiling and prognosis-associated factors of clear cell renal cell carcinoma (RCC), the most common entity in kidney cancer. Following VHL , PBRM1 , SETD2 , BAP1 , and KDM5C have been validated as the most common co-occurring gene mutations in clear cell RCC by multicenter studies. However, the morphological features of clear cell RCC with co-occurring gene mutations remain unclear. In this study, we presented 20 clear cell RCCs that underwent next-generation sequencing, of which 1 tumor was reclassified as ELOC -mutated RCC...

Desmoid fibromatosis is a myofibroblastic neoplasm of intermediate biologic potential, which has a strong predilection for local recurrence but does not metastasize. Arranged in long, sweeping fascicles with infiltrative borders, desmoid fibromatosis typically consists of uniform, bland myofibroblastic spindle cells that harbor mutation of CTNNB1 (or less often APC ) . In this report, we present a remarkable case of desmoid fibromatosis associated with striking nuclear pleomorphism. We hypothesize that this striking pleomorphism is due to a germline TP53 mutation, a finding first suspected due to strong and diffuse p53 staining by immunohistochemistry and subsequently confirmed by molecular testing...

Different authors have recently described a subtype of lipoma characterized by variation of adipocyte size, single cell fat necrosis, and a subset with minimal to mild nuclear atypia, and termed these as anisometric cell/dysplastic lipoma (AC/DL). These lipomas follow a benign course and rarely recur. In 3 examples, AC/DL has occurred in patients with childhood retinoblastoma (RB). We report another such example where multiple AC/DL occurred in the neck and back of a 30-year-old male who had germline RB1 gene deletion and bilateral RB in infancy...

Gastric undifferentiated/rhabdoid carcinoma is a rare highly invasive tumor of epithelial origin. Due to mutations in the switch/sucrose non-fermentable (SWI/SNF) complex, these tumor cells are usually dedifferentiated, presenting a characteristic rhabdoid profile. In this report, we present a gastric rhabdoid carcinoma in a 77-year-old man who presented with intermittent epigastric pain. Gastroscopy revealed a giant ulcer in the antrum, which proved to be a malignant tumor in the biopsy. Therefore, he was admitted to our hospital and underwent laparoscopic radical gastrectomy and D2 lymphadenectomy...

Adenocarcinomas with enteroblastic differentiation are rare clear cell tumors that are positive for enteroblastic markers. Enteroblastic differentiation is particularly uncommon in colorectal adenocarcinomas. Herein, we report a case of clear cell adenocarcinoma with enteroblastic differentiation in the sigmoid colon of a 38-year-old Japanese woman that metastasized to the lower left ureter. After neoadjuvant chemotherapy, the patient underwent low anterior resection. The tumor consisted of tubular, cribriform, and focal micropapillary proliferation of clear cells immunopositive for spalt-like transcription factor 4 (SALL4), glypican 3, and alpha-fetoprotein...

Introduction. Carcinoma with sarcomatoid components is a highly malignant tumor exhibiting both epithelial and stromal malignant differentiation. Its tumorigenesis is associated with epithelial-mesenchymal transition (EMT), and phenotypic changes from carcinoma to sarcoma are associated with TP53 mutations. Case presentation. A 73-year-old female with bloody stool was diagnosed with rectal adenocarcinoma. She underwent trans-anal mucosal resection. Histopathologically, the tumor cells showed 2 morphologically distinct populations...

Transmural fibrosis and stricture formation are key pathogenic processes for Crohn's disease that underlies clinical refractoriness, resulting in severe morbidity. The mechanisms for fibroplasia in Crohn's are not fully elucidated. In this study, we identified a cohort of refractory Crohn's disease with surgically resected bowel specimens including cases with bowel stricture and age-/sex-matched refractory disease without bowel stricture. Via immunohistochemistry, density and distribution of IgG4+ plasma cells in resected cases were analyzed...

Erdheim-Chester disease (ECD) is a rare non-Langerhans cell histiocytosis (LCH) that results in multiorgan disease involving the skin, bones, lungs, and kidneys. Female reproductive system manifestation of ECD was rare. Herein, we report a case of ECD involving the left ovary and fallopian tube. A 69-year-old woman presented with abdominal pain for 20 days. Magnetic resonance imaging revealed a solid and cystic mass on the left pelvic cavity. Histological examination revealed ovarian and fallopian tube infiltration by abundant histiocytes, with single small nuclei and foamy cytoplasm, reactive small lymphocytes, and plasma cells...

GLI1-altered mesenchymal tumor is an emerging entity with distinctive clinicopathologic features. It shows a distinctive monomorphic round to epithelioid morphology, nested to trabecular pattern of growth, and S100+/SOX10-/SMA-immunophenotype. We report an example of this entity arising in the duodenum. A 31-year-old man presented with anemia for 1 year, a mass in the duodenal bulb was found for 9 days. Histopathologic examination revealed the tumor with distinct multilobulated architecture, a monomorphic appearance of round to epithelioid cells arranged in papillary structures, nests, cords, solid, reticular patterns, and hyalinized stroma surrounding a rich capillary network...

Fibrin-associated large B-cell lymphoma is a rare microscopic-sized tumor, typically representing an unexpected finding at sites rich in chronic fibrin deposition. It is associated with Epstein-Barr virus, and has been reported to occur in a wide variety of anatomic sites and clinical scenarios. We report a case arising in a thyroid hyperplastic nodule, only the second case reported in this location. Notably, this is only the fourth case of fibrin-associated large B-cell lymphoma that is not associated with Epstein-Barr virus...

Dedifferentiated carcinoma of the female genital tract is a relatively recently recognized aggressive tumor affecting predominantly perimenopausal and postmenopausal women. In addition to having an undifferentiated component, dedifferentiated carcinoma includes a juxtaposed endometrioid adenocarcinoma, FIGO grade 1 or 2. Molecular characterization of these tumors has been a subject of discussion in multiple recent articles. We present a case of dedifferentiated carcinoma of the ovary in a 70-year-old female demonstrating concurrent inactivation of ARID1A and ARID1B ...

Background. Carcinoid-like pattern in basal cell carcinoma is extremely rare and has only been documented in a textbook. The aim of this study is to reveal the characteristics of the carcinoid-like pattern in basal cell carcinoma as well as to establish the concept of the tumor pattern. Methods. Of 355 basal cell carcinoma cases (355 lesions of 308 patients), 11 tumors with histopathological features of carcinoid-like pattern were retrieved. Results. The patients included 5 males and 6 females with a median age of 73 years (range 38-86 years)...

Gastric mucosal biopsies and resections from patients treated with neoadjuvant radiation and/or chemotherapy are frequently encountered. These samples may show histologic features related to therapy including inflammation, ulceration, and epithelial atypia. In some cases, epithelial atypia may be marked, prompting the use of adjunct p53 immunohistochemistry. We examined p53 expression by immunohistochemistry in gastric mucosa following therapy. We evaluated the histology and p53 immunohistochemical expression in gastric mucosa from 5 7 resections and 3 mucosal biopsies, from 60 patients treated with radiation and/or chemotherapy for gastroesophageal carcinoma (n  =  33) or pancreatic carcinoma (n  =  27)...

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Gastroblastoma is an extremely rare biphasic tumor that typically occurs in the stomach in patients between the ages of 10 and 30. Only 16 cases have been reported previously. These tumors are important to diagnose and distinguish from more aggressive neoplasms; although numbers are small, prognosis appears excellent overall with complete excision, with only occasional metastasis and/or local recurrence. We report a case of gastroblastoma in a 26-year-old male arising from the pylorus and extending through the first and second portions of the duodenum...

The molecular pathogenesis of breast fibroepithelial tumors continues to be elucidated. Recently, highly recurrent MED12 mutations arising in exon 2 at codon 44 were discovered in fibroadenomas and phyllodes tumors. In addition, a high prevalence of TERT promoter mutations in two hotspots (124 and 126 bp upstream from the translation start site) was discovered in up to 65% of phyllodes tumors. Breast periductal stromal tumors are a potentially distinct category of fibroepithelial lesions that are exceptionally rare with controversial classification and pathogenesis...

Systemic lupus erythematosus (SLE) is an autoimmune disease with various clinical presentations. Mucin deposition is a characteristic finding in skin lesions, but it is rare in other organs. We present a case with erythematous patches from the terminal ileum to the anus in an SLE patient. Diffuse colitis was diagnosed clinically. However, in addition to inflammatory cell infiltration, there was abundant mucinous material deposition in the submucosa. The mucinous material was positive for Alcian blue staining (pH 2...

Background. Although tumor size is regarded as the "T" stage of the tumor-node-metastasis (TNM) staging system for many solid tumors, its prognostic impact in gastric cancer remains uncertain and conflicting. Methods. We enrolled 6960 eligible patients from the Surveillance, Epidemiology, and End Results (SEER) database. The X-tile program was used to select the best cut-off value of tumor size. Then, the Kaplan-Meier method and the Cox proportional hazards model were applied to examine the efficacy of tumor size on prognostic prediction for overall survival (OS) and gastric cancer-specific survival (GCSS)...