Mesonephric Adenocarcinoma of the Uterine Corpus: Report of 2 Cases and Review of the Literature.

Mesonephric adenocarcinoma (MNA) is believed to arise from benign mesonephric remnants or hyperplasia located in the lateral walls of the uterine cervix. They are uncommon in other sites of the gynecologic tract, and exceptionally rare in the uterine corpus. So far, only 30 cases of uterine MNA have been reported in the literature, as a result, the etiology, clinical behavior, choice of treatment, and histogenesis of uterine MNA are still unclear. In this study, we report 2 cases of MNA of uterine corpus. One case involved the inner half of myometrium with endometrial involvement; the second case involved the outer half of myometrium without endometrial involvement. We also reviewed the clinical and pathologic presentations of this rare entity, and discussed the histogenesis of uterine corpus MNA based on recent molecular findings.

Structure and activation mechanism of the CHK2 DNA damage checkpoint kinase.

The CHK2 protein kinase is an important transducer of DNA damage checkpoint signals, and its mutation contributes to hereditary and sporadic cancer. CHK2 activation is triggered by the phosphorylation of Thr68 by the DNA damage-activated ATM kinase. This leads to transient CHK2 dimerization, in part through intermolecular phosphoThr68-FHA domain interactions. Dimerization promotes kinase activation through activation-loop autophosphorylation, but the mechanism of this process has not been clear. The dimeric crystal structure of CHK2, described here, in conjunction with biochemical and mutational data reveals that productive CHK2 dimerization additionally involves intermolecular FHA-kinase domain and FHA-FHA interactions. Ile157, mutated in the Li-Fraumeni cancer-predisposition syndrome, plays a central role in the FHA-kinase domain interface, explaining the lack of dimerization and autophosphorylation of this mutant. In the dimer, the kinase active sites face each other in close proximity, indicating that dimerization may also serve to optimally position the kinase active sites for efficient activation loop transphosphorylation.

Clinicopathologic Characterization of Sarcina ventriculi in the Upper Gastrointestinal Tract.

The bacterium Sarcina ventriculi (SV) is rarely identified in the upper gastrointestinal (GI) tract and has been associated with diverse clinical presentations. We aimed to characterize the clinicopathologic features of SV in the GI tract. Seventeen specimens (3 gastrectomy and 14 biopsy specimens) with histologic diagnosis of SV were identified and analyzed. The patients (9 female, 8 male) had a median age of 65 (range 32-86) years. Five (30%) patients presented acutely with GI bleeding or altered mental status. Other relevant symptoms included abdominal pain (n = 6, 35%), diarrhea (n = 4, 24%), dysphagia/dyspepsia (n = 3, 18%), and nausea/vomiting (n = 3, 18%). SV organisms were mainly identified in the stomach (n = 14, 82%), rarely at the gastroesophageal junction (n = 2, 12%), esophagus (n = 2, 12%), or duodenum (n = 1, 6%). Endoscopically, retained food debris was found in 5 of 13 (38%) examined patients. Histologically, the majority of specimens (12 out of 17, 71%) showed mild alterations including reactive gastropathy, inactive gastritis, or reflux (Grade 1). The other 5 specimens (29%) demonstrated erosion, ulcer, necrosis, or perforation (Grade 2). The most commonly associated comorbidities were diabetes mellitus (n = 10, 59%), gastroparesis/outlet obstruction (n = 10, 59%), and gastroesophageal reflux disease (n = 6, 35%). Upon follow-up, 3 (18%) patients with acute phlegmonous gastritis died shortly after gastrectomy. Our case series, the largest reported so far, describes a spectrum of histologic severity associated with SV infection. Diabetes and gastroparesis/outlet obstruction manifested as retained food debris endoscopically are common findings with SV, and may provide a growth medium for this organism and provoke pathogenicity contributing to fatality in acute conditions.

Deployment and assessment of a deep learning model for real-time detection of anal precancer with high frame rate high-resolution microendoscopy.

Anal cancer incidence is significantly higher in people living with HIV as HIV increases the oncogenic potential of human papillomavirus. The incidence of anal cancer in the United States has recently increased, with diagnosis and treatment hampered by high loss-to-follow-up rates. Novel methods for the automated, real-time diagnosis of AIN 2+ could enable "see and treat" strategies, reducing loss-to-follow-up rates. A previous retrospective study demonstrated that the accuracy of a high-resolution microendoscope (HRME) coupled with a deep learning model was comparable to expert clinical impression for diagnosis of AIN 2+ (sensitivity 0.92 [P = 0.68] and specificity 0.60 [P = 0.48]). However, motion artifacts and noise led to many images failing quality control (17%). Here, we present a high frame rate HRME (HF-HRME) with improved image quality, deployed in the clinic alongside a deep learning model and evaluated prospectively for detection of AIN 2+ in real-time. The HF-HRME reduced the fraction of images failing quality control to 4.6% by employing a high frame rate camera that enhances contrast and limits motion artifacts. The HF-HRME outperformed the previous HRME (P < 0.001) and clinical impression (P < 0.0001) in the detection of histopathologically confirmed AIN 2+ with a sensitivity of 0.91 and specificity of 0.87.

Sinonasal Hamartomas: From Nasal Chondromesenchymal Hamartoma to Respiratory Epithelial Adenomatoid Hamartoma. Report of six Cases and Review of the Literature.

Sinonasal hamartomas are uncommon lesions of nasal and sinus cavities. Based on indigenous cellular components and characteristic histologic features, they are further classified into four entities: respiratory epithelial adenomatoid hamartoma (REAH), seromucinous hamartoma (SH), chondro-osseous and respiratory epithelial hamartoma (CORE), and nasal chondromesenchymal hamartoma (NCH). REAH, SH, and CORE are seen in adult patients, while NCH predominantly occurs in newborns and infants. Morphologically REAH and SH are composed of respiratory epithelium and seromucinous glands, CORE is related to REAH but with additional feature of chondroid and/or osseous tissue, and NCH is composed of chondroid and stromal elements but devoid of epithelial component. All four lesions can present as sinonasal mass lesions and with associated obstructive symptoms. Given the rarity of these lesions, diagnosis can be challenging, especially in unusual clinical scenario. In this study, we report six cases of sinonasal hamartoma, including one case of NCH, one case of CORE, two cases of SH, and two cases of REAH. All cases were from adult patients including four men and two women. We also review the literature of the clinical and pathologic features of these rare lesions.

BCOR-CCNB3 Sarcoma with Prominent Rhabdoid Cells Mimicking Rhabdomyoblasts: Expanding the Morphologic spectrum of BCOR-CCNB3 Sarcoma.

BCOR-CCNB3 sarcoma (BCS) is a rare recently defined undifferentiated sarcoma that predominantly affects children and young adults. The diagnosis of this tumor is difficult due to the highly variable morphology and nonspecific immunophenotype. Emerging data suggest that patients with BCS show response to Ewing sarcoma-based treatment regimen, thus correct diagnosis is of clinical relevance. In this study, we report a case of BCS arising from the big toe of a 15-year-old male patient. The tumor had a prominent population of rhabdoid cells with bright eosinophilic cytoplasm mimicking rhabdomyosarcoma. The tumor cells were focally positive for desmin and myogenin, and negative for CD99. Next-generation sequencing showed the presence of BCOR-CCNB3 gene fusion. BCS with prominent rhabdoid cells has not been described before. This study further expands the morphologic spectrum of BCS.

Obesity Is a Risk Factor Associated with H. pylori-negative MALT Lymphoma of Stomach.

OBJECTIVE: More than 90% of gastric mucosa-associated lymphoid tissue (MALT) lymphomas are attributed to Helicobacter pylori infections. However, the pathogenesis of H. pylori-negative MALT lymphomas is controversial, and additional etiologies need to be investigated. MATERIALS: A retrospective study of gastric MALT lymphoma cases over a 15-year period revealed 56 cases. The H. pylori status, clinical information, and body mass index (BMI) data were collected. The results of the urea breath test, serology, stool antigen, and previous biopsy results were documented. RESULTS: The 56 cases had an average height of 166.57 cm (range, 147.3-190.5), weight of 83.98 kg (range 55-153.1), and body mass index (BMI) of 30.34 kg/m2 (range, 17.96-49.77). Twenty-one cases were H. pylori-positive (37.5%), with a mean BMI of 27.36 kg/m2 (range, 17.96-47.25), and BMI>30 kg/m2 in 5 (23.8%) patients. Thirty-five cases were H. pylori-negative, with a mean BMI of 31.90 kg/m2 (range, 18.17-49.77), and 20 (57.1%) having BMI>30 kg/m2. A Fisher's exact test and two-tailed test showed a statistically significant difference between the two groups. CONCLUSION: Obesity leads to a baseline state of chronic inflammation and increased production of pro-inflammatory cytokines that can stimulate the lymphocytes, leading to lymphomatous proliferation. Our study suggests a potential correlation between obesity and the risk of development of primary gastric MALT lymphoma.

Morphoproteomics Identifies CXCR4 in Undifferentiated Colorectal Cancer: A Case Study with Therapeutic Implications.

Undifferentiated colorectal cancer (UCRC) has a well-documented CD44 cancer stem cell (CSC) component. CXCR4 (C-X-C motif receptor 4) also is a CSC marker and with its ligand, stromal-derived factor (SDF)-1 alpha has been shown to act in concert with CD44 to promote cancer cell invasion. To date, CXCR4 has not been reported in the MEDLINE (PubMed) literature with respect to UCRC. Morphoproteomic analysis, utilizing bright field microscopy, can visualize the intensity and cell location of protein analytes with a patient's tumor including CXCR4 expression and was applicable to this case study. Using morphoproteomic analysis we identified chromogenic expression of both CD44 on the plasmalemmal aspect of the majority of the undifferentiated colorectal cancer foci and CXCR4 expression on the plasmalemmal or cytoplasmic aspect in up to 50% of the tumor cells in some regions and also on the intratumoral endothelial cells in the patient's UCRC. Moreover, both CSC markers were retained in the foci showing incomplete mucinous differentiation. In the context of data mining of the scientific literature, these findings suggest a collaboration between CXCR4 and CD44 in promoting tumor invasion and angiodependent metastasis in UCRC. Therapies designed to inhibit both the CD44 and the CXCR4 pathways are available and could reduce the metastatic potential of UCRC.

Syphilis Causing Lichenoid Esophagitis.

We present a 50-year-old woman with human immunodeficiency virus admitted to the hospital for melenic stools and anemia who underwent esophagogastroduodenoscopy for evaluation of upper gastrointestinal bleed. She is found to have inflammation of the esophagus with ulcerations and crater formation. A biopsy reveals severe inflammation with lymphocytic infiltrates with civatte bodies suggestive of lichenoid esophagitis with the presence of spirochetes (Treponema pallidum). The presence of syphilis in the esophagus causing lichenoid esophagitis is an extremely rare presentation that has never been reported.

Esophageal necrosis associated with sodium polystyrene sulfonate (Kayexalate) use.

Acute esophageal necrosis is a rare cause of gastrointestinal bleeding. Endoscopically, it appears as a circumferential black-appearing mucosa affecting almost universally the mid and distal esophagus. Risk factors include low flow states, malnutrition, alcoholism, and the presence of multiple comorbidities. Prolonged exposure to gastric secretions and direct contact with corrosive agents also induce mucosal ischemia. Sodium polystyrene sulfonate use has been associated with severe gastrointestinal adverse events, including increased risk of small bowel and colonic necrosis and perforation. In susceptible individuals, sodium polystyrene sulfonate can also induce esophageal ischemia and necrosis, as illustrated in this case.

Fine needle biopsy of malignant tumors of the liver: a retrospective study of 624 cases from a single institution experience.

BACKGROUND: Liver is one of the most common organs involved by metastatic neoplasms. In addition, a number of primary tumors can arise in the liver. Fine needle biopsy (FNB) is the most commonly used method for diagnosis of liver masses. Not much literature is available during the past 10 years about FNB of liver tumors. All large studies were performed more than 15 years ago. With the introduction of new disease entities, new tumor classification systems, and new diagnostic methods, updated documentation of FNB of liver neoplasms is much needed. METHODS: Liver FNB cases that were diagnosed as "Positive for Malignancy" between 2010 and 2018 were retrieved from the cytopathology database in our institution. Patient medical records, cytopathology and surgical pathology reports, and slides from selected cases were retrieved and reviewed. RESULTS: Over 30 different types of malignant tumors were identified in 624 malignant FNB cases, with the most common tumors being metastatic colorectal and pancreatic adenocarcinomas. Rare tumors include EBV-positive leiomyosarcoma, mesothelioma, and paraganglioma, among others. A subset of patients presented with widespread metastases involving liver with no known history. Identifying the primary sites in those cases can be challenging. We also found that in our practice, a significant number of hepatocellular carcinoma were diagnosed by FNB in recent years. CONCLUSIONS: A tremendous variety of neoplasms can occur in liver. Accurate diagnosis is essential for proper patient management. Familiarization with morphological features and judicious usage of ancillary studies are essential for accurate diagnosis.

Desmoplastic Small Round Cell Tumor of Parotid Gland: A Rare Entity With Diagnostic Challenge.

Desmoplastic small round cell tumor (DSRCT) is a rare malignant mesenchymal neoplasm that typically affects young patients and presents as large intraabdominal masses. We report a rare case of parotid gland DSRCT in a 38-year-old man. The tumor cells were large sized and form irregular nests embedded in abundant desmoplastic stroma. Immunohistochemically, the tumor cells were positive for cytokeratin, GATA3, p40, and p63. Working differential diagnosis included squamous cell carcinoma, myoepithelial carcinoma, hyalinizing clear cell carcinoma, NUT (nuclear protein of the testis) carcinoma, and adamantinoma-like Ewing sarcoma. The characteristic morphologic features and presence of EWSR1-WT1 gene fusion are diagnostic of DSRCT. Salivary gland DSRCT is an exceedingly rare entity, with only 6 cases reported in the literature.

SATB2 and Hep Par 1 Immunohistochemistry Is Helpful in Distinguishing Between Inflamed and Architecturally Altered Ileal Pouch and Rectal Cuff Mucosa.

The management of patients with ulcerative colitis after proctocolectomy with ileal pouch-anal anastomosis includes independent histological assessments of inflammation in the ileal pouch and the rectal cuff. However, the distinction between pouchitis and cuffitis can be impeded both endoscopically and histologically by the combined effects of inflammation and regeneration. We investigated the use of 2 markers, hepatocyte paraffin 1 (Hep) and SATB2 (special AT-rich sequence-binding protein 2), which are expressed immunohistochemically in the small and large bowel epithelium, respectively, as ancillary methods to deal with this problem. Immunohistochemical staining was performed retrospectively on 20 consecutive pairs of post-ileal pouch-anal anastomosis biopsies with varying degrees of histological inflammation and architectural distortion, which had each been designated as "ileal pouch" or "rectal cuff" by the referring endoscopists. Expression was graded as focal (10% to 74% stained cells) or diffuse (75% to 100%). Among the ileal pouch biopsies, 20 (100%) expressed Hep either diffusely (75%) or focally (25%), whereas SATB2 staining was either negative in 15 (75%) or focal in 5 (25%), the latter group all expressing Hep diffusely. Among the rectal cuff biopsies, 14 expressed SATB2 diffusely. Of these, Hep was either negative in 11 (79%) or focally positive in 3 (21%), the latter group all expressing SATB2 diffusely. Six ostensibly rectal cuff biopsies (30%) expressed Hep diffusely and were negative for SATB2, suggesting endoscopic misidentification. None of the 40 biopsies expressed both markers diffusely. We conclude that in doubtful cases, diffuse expression of either Hep or SATB2 can be helpful in discriminating between ileal pouch and rectal cuff mucosa, respectively.

Uniform and Robust Nuclear Expression of HES1 in Neuroendocrine Neoplasms.

Introduction. Neuroendocrine neoplasms (NENs) are neoplasms that most commonly arise from gastrointestinal tract, pancreas, and lung. HES1 is a downstream target of Notch signaling pathway. The current literature about HES1 expression in NENs is sparse and inconsistent. Methods. In this study, we evaluated HES1 expression by immunohistochemistry in a total of 32 cases of NENs, including 13 well-differentiated neuroendocrine tumors from gastrointestinal tract, 10 cases of well-differentiated neuroendocrine tumors of pancreas, 9 cases from lung, including 4 cases of typical carcinoid, 1 case of atypical carcinoid, and 4 cases of neuroendocrine carcinoma. The intensity of the stain was scored from - to +++, and the distribution of the staining of HES1 was evaluated. Results. HES1 demonstrates uniform robust (+++) nuclear staining pattern in the tumor cells of all the NENs (32/32), regardless of the origin of the system and the grade of the tumor. Conclusions. HES1 is uniformly expressed in NENs with robust nuclear expression pattern. Our finding suggests that NOTCH1 or HES1 inhibitor is a potential therapeutic choice for neuroendocrine neoplasms.

Fetal Type Rhabdomyoma of the Soft Palate in an Adult Patient: Report of One Case and Review of the Literature.

Rhabdomyoma is a rare benign tumor with skeletal muscle differentiation. Rhabdomyoma is further classified into cardiac, adult, fetal, and genital subtypes. Out of these, fetal type rhabdomyoma (FTR) is the rarest. Only a small number of cases have been recorded in the literature. FTR typically affects male infants and young children and occurs predominantly in the head and neck region. FTR is exceedingly rare in the adult, with less than 30 cases reported. The classic FTR is composed of primitive undifferentiated spindle cells with scant eosinophilic cytoplasm embedded in a myxoid stroma. Immunohistochemically, the tumor cells are positive for desmin, muscle specific actin, and myogenin. Awareness and proper recognition of this rare entity is of considerable importance to avoid misdiagnosis of embryonal rhabdomyosarcoma. In this study, we report one case of FTR in an adult patient and reviewed the literature about the clinical and pathologic presentation of FTR in the adult.

Epstein-Barr Virus-Positive Large Cell Neuroendocrine Carcinoma of the Nasopharynx: Report of One Case and Review of the Literature.

Epstein-Barr Virus (EBV)-positive neuroendocrine carcinoma (NEC) of the nasopharynx is exceedingly rare, only two cases have been reported in the literature. While EBV infection is strongly associated with nasopharyngeal carcinoma, which is carcinoma with squamous differentiation, the link between EBV and NEC is not well known, and can be diagnostically challenging. In this study, we report the third case of EBV-positive large cell NEC of nasopharynx with neck lymph node metastasis. The patient was treated with combined radiation and chemotherapy and showed complete clinical and radiological response. Similar treatment response has been reported in another patient with high stage EBV-positive large cell NEC, suggesting that EBV status is an important prognostic factor. Recognition of this rare tumor is important for disease management and patient prognosis. We also review the literature about the clinical and pathologic presentation of neuroendocrine tumors of nasopharynx.

Sinonasal undifferentiated carcinoma: clinicopathological spectrums and diagnosis reappraisal.

Sinonasal undifferentiated carcinoma (SNUC) is defined as undifferentiated carcinoma of the sinonasal tract without glandular or squamous features and not otherwise classifiable. SNUC is a rare tumor, with a long list of differential diagnoses, and often poses a considerable diagnostic challenge. In addition, recent advances in molecular and immunohistochemistry techniques have recognized several new entities that were previously included in the SNUC category. These include SMARCB1 (INI-1)-deficient carcinoma, NUT (nuclear protein in testis) carcinoma, adamantinoma-like Ewing sarcoma, and the most recently described and rarer SMARCA4 (BRG)-deficient carcinoma. In this study, we retrospectively reviewed 11 cases with an original diagnosis of SNUC. We found that a significant portion of those cases can be reclassified into specific entities, with potential impact on therapy and prognosis because of misclassification in 2 of these cases.

Low Grade Carcinoma Ex-Pleomorphic Adenoma: Diagnosis and Diagnostic Challenges Caused by Fine Needle Aspiration: Report of Three Cases and Review of Literature.

Low grade carcinoma ex pleomorphic adenoma (LG CXPA) is a rare low grade malignant neoplasm arising from preexisting pleomorphic adenoma (PA). LG CXPA demonstrates no overt cytological atypia, and can be difficult to distinguish from cellular PA. Invasive growth is one of the hallmarks of LG CXPA, e.g., tumor extends beyond the capsule and into adjacent non-neoplastic tissue. However, it is known that capsular and vascular invasion, as well as the presence of stroma-rich PA in soft tissue without a capsule (pseudopodia) can be seen in PA. These histological findings have no prognostic significance and are not diagnostic of malignancy. In addition, recurrent PA typically presents as numerous nodules extending into soft tissue and skeletal muscle, which again are not considered malignant features. Thus, "infiltrative growth" of LG CXPA is difficult to define and diagnosis is challenging to many practicing pathologists. In this study, we report three cases of LG CXPA. We review the diagnostic criteria for LG CXPA, and discuss the diagnostic challenges caused by fine needle aspiration (FNA) changes. FNA is widely used as a cost-effective, quick and accurate method for diagnosing salivary gland lesions. Histological changes post-FNA are usually focal and mild, and are not causes of diagnostic difficulties. According to our knowledge, this is the first report of LG CXPA complicated with FNA changes.

P16-positive cystic squamous cell carcinoma in midline neck: metastasis from oropharynx or primary carcinoma arising from thyroglossal duct cyst?

Cystic squamous cell carcinoma (SCC) of the lateral neck is considered metastatic human papilloma-virus (HPV)-related oropharyngeal SCC (HPV-OPSCC) until proven otherwise. P16 immunohistochemistry is diffusely positive in those carcinomas and is used as a surrogate marker of active human papillomavirus (HPV) infection. Thyroglossal duct cysts (TDC) are one of the differential diagnoses for cystic neck lesions. SCC arising from TDC is extremely rare. In this study, we report a p16-positive cystic SCC located in the midline neck. Radiologic features and the presence of thyroid tissue in the cyst wall indicated that it was a TDC. The morphologic features of the lesion raised the question: is the carcinoma metastatic HPV-OPSCC? The HPV confirmative test, high-risk HPV RNA in situ hybridization, was negative. We then studied p16 immunohistochemistry in the squamous epithelium of benign TDC and found that rare benign TDC can show diffuse and strong p16 positivity.

Luminally polarized mural and vascular remodeling in ileal strictures of Crohn's disease.

Intestinal stricture, a major complication of Crohn's disease (CD), results from fibromuscular remodeling and expansion of the intestinal wall. The corresponding microanatomical alterations have not been fully described, hindering progress toward understanding their pathogenesis and devising appropriate treatments. We used tissue-specific staining and quantitative digital histomorphometry for this purpose. Serial histologic sections from 37 surgically resected ileal strictures and adjacent nonstrictured controls from patients with CD were evaluated after staining for smooth muscle actin, collagen (Sirius red), and collagen types I, III, and V. Overall mural thickening in strictures was increased 2.2 ±â€¯0.2-fold compared with nonstrictured regions of the same specimens. The muscular layer most altered was the muscularis mucosae (MM). Compared with the internal and external layers of the muscularis propria, (MP) which were expanded 1.9 ±â€¯0.2- and 1.3 ±â€¯0.1-fold, respectively, the MM was expanded 17.7 ±â€¯2.6-fold, reflecting the combined effects of architectural disarray, an 11.6 ±â€¯1.4-fold increase smooth muscle content, and elaboration of pericellular type V collagen. In contrast, the architecture of the MP was preserved and pericellular collagen was virtually absent; rather, fibrosis in this layer was limited to expansion of the intramuscular septa by collagen types I and III. The muscular arteries and veins within the strictured submucosa frequently exhibited eccentric, luminally oriented adventitial mantles comprising hyperplastic myocytes and extracellular type V collagen. We conclude that the fibromuscular remodeling which results in CD-associated ileal strictures predominantly involves the MM and submucosal vasculature in a luminally polarized fashion and suggests that mucosal-based factors may contribute to stricture pathogenesis.