MDM2 Amplification Status in a Cohort of Well-Characterized Myxofibrosarcoma: A Clinicopathologic Analysis of 22 Tumors.

Myxofibrosarcomas (MFS) present as slowly enlarging superficial masses in elderly patients. Even though these tumors fail to exhibit a distinct immunophenotype, diagnosis is straightforward when they present in subcutaneous tissue. Intramuscular MFS, however, are more challenging to diagnose as the differential also includes dedifferentiated liposarcoma with myxoid features. The vast majority of dedifferentiated liposarcomas show MDM2 amplification, whereas limited data exists as to the MDM2 status of MFS. We sought to explore the rate of MDM2 amplification in cases of classic MFS. Our archives were searched for MFS; only subcutaneous well-sampled resections were included. FISH for MDM2 amplification was performed on each tumor. A cohort of myxoid dedifferentiated liposarcoma resections was studied for comparison. Twenty-two MFS arose in patients aged 44 to 85 years. All tumors contained an infiltrative population of atypical cells embedded in a myxoid stroma with curvilinear blood vessels. MDM2 amplification by FISH was identified in 3 (of 22; 14%) tumors. Available follow up on 17 patients (range 1-96 months; median 13 months) revealed 6 patients with local recurrence and 1 with distant metastasis. Of 3 patients with MDM2- amplified MFS, 1 experienced recurrence and died of unrelated causes, while the second was alive without disease 12 months after diagnosis. Even though the rate of MDM2 amplification by FISH in MFS appears to be low, a subset of cases may show this genetic alteration, which pathologists should be aware of to avoid misclassification as myxoid dedifferentiated liposarcomas. Further studies are necessary to determine if amplification status adds prognostic value.

Novel NCOA2/3-rearranged low-grade fibroblastic spindle cell tumors: A report of five cases.

Spindle cell mesenchymal neoplasms are a diverse and often challenging diagnostic group. While morphological impression is sufficient for some diagnoses, increasingly immunohistochemical and even molecular data is required to render an accurate diagnosis, which can lead to the characterization of new entities. We describe five cases of novel mesenchymal neoplasms with rearrangements in the NCOA2 and NCOA3 genes partnered with either CTCF or CRTC1. Three tumors occurred in the head and neck (palate, auditory canal), while the other two were in visceral organs (lung, urinary bladder). All cases occurred in adults (range 33-86) with a median age of 42 and fairly even sex distribution = (male-to-female = 3:2). Morphologically, they had similar features consisting of monotonous, bland spindle to ovoid cells with fascicular and reticular arrangements in a myxohyaline to collagenous stroma. However, immunophenotypically they had essentially a null phenotype, with only two tumors staining partially for CD34 and smooth muscle actin. Targeted RNA sequencing detected in-frame CTCF::NCOA2 (one case), CRTC1::NCOA2 (two cases), and CTCF::NCOA3 (two cases) fusions. Treatment was surgical resection in all cases. Local recurrence and/or distant metastases were not observed in any case (median follow-up, 7.5 months; range, 2-19 months). Given their morphologic, immunohistochemical, and molecular similarities, we believe that these cases may represent an emerging family of low-grade NCOA2/3-rearranged fibroblastic spindle cell neoplasms.

Keratin-Positive Giant Cell-Rich Tumor of Bone Harboring an HMGA2::NCOR2 Fusion: Two Cases, Including a Patient With Metastatic Disease, and Review of the Literature.

Giant cell-rich lesions of bone represent a heterogeneous group of entities which classically include giant cell tumor of bone, aneurysmal bone cyst, nonossifying fibroma, and Brown tumor of hyperparathyroidism. A recently described subset of giant cell-rich tumors involving bone and soft tissue has been characterized by recurrent HMGA2::NCOR2 fusions and keratin expression. The overlapping clinical, radiographic, and morphological features of these giant cell-rich lesions provide a unique diagnostic challenge, particularly on biopsy. We present 2 additional cases of keratin-positive giant cell-rich tumor of bone with HMGA2::NCOR2 fusions, including 1 patient who developed metastatic disease.

Immunotactoid hepatopathy: A novel entity with histologically proven recurrence post liver transplantation.

Immunotactoid deposition is a rare fibrillary deposition disease that is primarily seen in the kidney and is associated with paraproteinemia. Here, we report a case of hepatic immunotactoid deposition in a 67-year-old male with a history of smoldering myeloma and chronic kidney disease who underwent liver transplantation for metabolic dysfunction-related cirrhosis. Immunotactoid deposition was first identified in the explanted liver and recurred in the allograft within only 7 weeks following transplantation, presenting as ascites with normal liver function tests. The patient's posttransplant course was complicated by proteinuria and renal failure requiring dialysis. Histologic examination of both native and allograft livers demonstrated pink amorphous material occupying sinusoidal spaces that were Congo-red negative and immunoglobulin M Kappa-restricted. Electron microscopy revealed characteristic deposits of electron-dense bundles of hollow microtubules with a 40 nm diameter within the sinusoids and space of Disse, consistent with immunotactoids. Therapy of the patient's underlying plasma-cell dyscrasia utilizing a daratumumab-based regimen showed decreased serum paraproteins, resolution of ascites, and improved kidney function, no longer requiring dialysis, without inducing rejection. The patient continues to respond to treatment 10 months posttransplant.

Superficial desmoplastic fibroblastoma (collagenous fibroma): Clinicopathologic study of 11 cases.

BACKGROUND: Desmoplastic fibroblastoma (collagenous fibroma) is a rare soft tissue tumor that usually arises in the subcutis or skeletal muscle. Cases superficial to fascia are unusual and can cause diagnostic difficulty. We present 11 cases of superficial desmoplastic fibroblastoma involving a wide anatomic distribution. METHODS: Archives were searched using the term "desmoplastic fibroblastoma" over a 10-year period (2012-2022). Cases superficial to fascia were retrieved, and available clinicopathologic features were recorded. Only cases involving the dermis were included. RESULTS: Eleven cases were identified, all of which were received in consultation. Tumors involved the head and neck (2), lower extremity (2), back (2), foot (1), shoulder (1), axilla (1), hand (1), and breast (1). Each consisted of a hypocellular proliferation of bland stellate to spindled fibroblasts set in a collagenous to focally myxoid stroma. The immunohistochemical stains available for review demonstrated SMA positivity (4/7) and negative immunoreactivity for CD34 (0/6), EMA (0/3), desmin (0/3), and S100 (0/7). CONCLUSIONS: Desmoplastic fibroblastoma may present superficially in the dermis to subcutis, posing a potential source of diagnostic difficulty. Recognition of the characteristic histopathologic features of desmoplastic fibroblastoma with judicial use of immunohistochemical stains should allow for accurate diagnosis.

Acute Appendicitis as the First and the Only Presentation of Systemic Mastocytosis.

Systemic mastocytosis is a rare myeloproliferative disorder characterized by abnormal accumulation of mast cells in a variety of organs. When affecting the gastrointestinal tracts, it may manifest with steatorrhea, malabsorption, hepatomegaly, splenomegaly, portal hypertension, and ascites, among others. To our knowledge, only one case of systemic mastocytosis has been reported affecting the appendix. We present another case of a 47-year-old woman who was admitted for right-sided acute abdominal pain and found to have systemic mastocytosis in her appendectomy specimen as the first and only manifestation of her disease.

Novel NONO::TFE3 fusion and ALK co-expression identified in a subset of cutaneous microcystic/reticular schwannoma.

Microcystic/reticular schwannoma (MRS) is a benign variant of schwannoma with a predilection for the gastrointestinal tract and skin. To date, genetic characterization of this tumor is limited. Prompted by the identification of TFE3::NONO fusion and ALK overexpression in an index case of MRS, a cohort of tumors was collected from institutional and consultation archives of two institutions. Next-generation sequencing (NGS), TFE3 fluorescence in situ hybridization (FISH), and TFE3 and ALK immunohistochemistry were performed, while clinicopathologic variables were documented. Eighteen MRS cases were identified (35 to 85 years) arising in the skin (n=8), gastrointestinal tract (n=5), adrenal gland (n=3), abdominal wall (n=1), and unknown site (n=1). Tumors showed a circumscribed to multinodular to plexiform low-power architecture with variable amounts of microcystic/reticular and solid schwannian components. Mitotic figures were scarce (0-1/10 HPFs), and atypia was absent. S100 protein and/or SOX10 immunoreactivity was noted in the microcystic/reticular and schwannian areas of all cases. NGS performed on two cutaneous tumors yielded NONO exon 12 fusion with TFE3 exon 4, and these lesions also showed HMB45 and ALK expression. Two additional cases showed ALK expression (1 weak), while a third was positive for TFE3, but these cases failed to show ALK or TFE3 rearrangement by FISH/NGS. There were no morphologic variables that correlated with the presence of NONO::TFE3. We identified a subset of microcystic/reticular schwannomas with NONO::TFE3 fusions and ALK co-expression, adding to the cohort of mesenchymal neoplasms that show ALK overexpression without rearrangement of the ALK gene.

Inhibin-Positive "Cholangioblastic" Variant of Intrahepatic Cholangiocarcinoma: Report of 3 New Patients With Review of the Literature.

Cholangiocarcinoma is the second most common primary liver malignant neoplasm. It usually affects older individuals in their seventh decade of life with no gender predilection. Recently, a distinct subtype of cholangiocarcinoma has emerged with 2 proposed names: "cholangioblastic" and "solid tubulocystic." This variant predominantly occurs in younger women who lack the common risk factors for patients diagnosed with cholangiocarcinomas, such as older age and chronic liver disease or cirrhosis. We describe 3 new patients with a cholangioblastic variant of intrahepatic cholangiocarcinoma. At the time of diagnosis, the patients were aged 19-, 46-, and 28-year-old; 2 females and 1 male (the 46-year-old). None of our patients had a history of chronic liver disease or known predisposing factors for liver tumors. Tumor size ranged from 2.3 to 23 cm in greatest dimension. Histological examination of these tumors demonstrated reproducible morphology characterized by trabecular, nested, and multicystic patterns with micro and macro follicles filled with eosinophilic material. The immunohistochemical profile showed that the tumor cells were positive for keratin 7, inhibin, synaptophysin, and albumin in situ hybridization, while negative for HepPar1, arginase, and INSM1. All tumors lacked conventional intrahepatic cholangiocarcinoma/adenocarcinoma morphology. We also review the literature and emphasize that neuroendocrine tumors should be recognized as a major diagnostic pitfall of this variant.

High-grade large cell neuroendocrine carcinoma of the esophagus: a case report and review of the literature.

BACKGROUND: Neuroendocrine carcinomas are extremely rare in the esophagus as they represent less than 0.04% of all neuroendocrine tumors. To date, only 14 cases of poorly differentiated, high-grade esophageal NEC have been described in the literature. The majority of these patients presented with typical dysphagia symptoms. Due to its rarity, no standardized guidelines have been proposed to treat esophageal neuroendocrine carcinoma, although general recommendations suggest surgery with adjuvant chemoradiotherapy as the treatment of choice. CASE PRESENTATION: A 67-year-old previously healthy White male presented with a year-long intermittent nonspecific retrosternal discomfort, with the absence of any other symptoms. Esophagogastroduodenoscopy revealed an ulcerative mass in his lower esophagus, with concern of malignancy. Endoscopic ultrasound-guided biopsy revealed poorly differentiated neuroendocrine carcinoma of the esophagus with metastasis to a diaphragmatic lymph node. He was treated with neoadjuvant chemoradiation followed by surgery, and he has been in remission for over 5 years. CONCLUSION: Here, we review the literature and report a unique case of a patient with a vague presentation of esophageal neuroendocrine carcinoma as he enters his sixth year of survival following neoadjuvant chemoradiotherapy.

Perforating Colitis Secondary to Immune Checkpoint Inhibitor Use in a Patient With Pericolonic Involvement by Rosai-Dorfman Disease.

Recently, the use of immunotherapy has increased substantially for the treatment of several malignancies. It is associated with several gastrointestinal adverse events; however, severe complications such as intestinal perforation are rare. We present a 75-year-old man with metastatic melanoma, presented with profuse diarrhea and abdominal pain, after ipilimumab and nivolumab administration. Shortly after, he developed fulminant colitis and intestinal perforation and was found to have concurrent Rosai-Dorfman disease of pericolonic lymph nodes. With the increasing use of immunotherapy, reporting of serious adverse events and their mimics is essential. In addition, further studies are required to investigate whether an association exists between Rosai-Dorfman disease and immunotherapy.

The Histopathology of Neoadjuvant-Treated (NAT) Pancreatic Ductal Adenocarcinoma.

Examination of pancreatic ductal adenocarcinoma after NAT with the intent of diagnosis and outcome prediction remains a challenging task. The lack of a uniform approach to macroscopically assess these cases along with variations in sampling adds to the complexity. Several TRG systems have been proposed to correlate with an overall survival. In clinical practice, most of these TRG schemes have shown low level of interobserver agreement arguing for a need of larger studies and more innovative ways to assess outcome in this population.

Successive waves of COVID 19: confinement effects on virus-prevalence with a mathematical model.

BACKGROUND: A pandemic outbreak of severe acute respiratory syndrome coronavirus 2 (COVID 19) incidence data are largely available online. Until August 17, COVID 19 has hit more than 22 million individuals all over the globe. So, it is urged to get clear information about the prevalence of the virus. Therefore, one can manipulate easily a suitable mathematical model to fit these published data. METHODS: We propose a mathematical model that considers the total population, in 25 countries, either infected by COVID 19 or confined (safe) during the period from November 17, 2019, to August 17, 2020. The model considers the total population as a complex number; the imaginary part is the number of infected individuals and the real part is the number of confined individuals. This classification combined with mathematical treatments leads to a transmission dynamics of the virus to be as wave-like motion. The virus can hit any country either by one wave or by successive waves (up to 11 waves). FINDINGS: We find net discrimination between the 25 countries investigated in this report. The immediate response to the first attack is a substantial parameter to determine whether the epidemic attack will be in one wave or it can be in successive waves. For example, the best case was such as individuals in China hit by one wave while the individuals in the USA were attacked by nine waves; it is the worst case all over the globe. In addition, the model differentiates between the daily reproduction numbers (Rd0) and the median reproduction number (R0). We have found that Rd0 decreases exponentially with time from high values down to zero at the wave maximum point; and R0 varies from a country to another. For example, the virus hit individuals in Germany in R0 = 1.39 (96% CI 1.01-3.87) and in the USA R0 = 3.81 (91% CI 1.71-5.15). We have found that twice the virus has hit both the USA and Iran. The great protestation of black matter lives in the USA and the great assemblage of the new Iranian year, on March 21, 2020, have been the cause of the second epidemic attack in both countries. INTERPRETATION: Our results show that COVID 19 transmission depends on the prompt reaction against the first viral-wave. The reaction depends on both the social behaviour of individuals and on the swift system-decision by the governmental decision-maker(s). The Chinese strictly follow the decision-maker and therefore the virus hit by only one wave; while in the USA, the system-decision was different and the American-responses were different, therefore ten waves followed the first wave.

SMARCA4/SMARCA2-deficient Carcinoma of the Esophagus and Gastroesophageal Junction.

Undifferentiated carcinoma of the esophagus and gastroesophageal junction is a recently recognized entity in the fifth edition of the World Health Organization Classification of Digestive Tumors and is diagnostically challenging, particularly on small biopsies. SMARCA4 and SMARCA2 are chromatin remodeling genes with key roles in oncogenesis. We retrieved 14 cases of SMARCA4/SMARCA2-deficient undifferentiated carcinoma of the gastroesophageal junction and esophagus from the authors' institutions. The tumors showed similar histologic findings: the sheet-like proliferation of tumor cells characterized by discohesion, large nuclei, and prominent macronucleoli with many tumor cells exhibiting a rhabdoid appearance. In 8 cases, adjacent specialized intestinal metaplasia was noted and 3 cases exhibited adjacent high-grade dysplasia. Immunohistochemically, tumors variably expressed keratins and disclosed loss of expression of SMARCA4 in 12 and SMARCA2 in 7 cases. In 2 cases SMARCA2 alone was lost without SMARCA4 loss. A mutant p53 immunohistochemical pattern was seen in 4 of 4 cases, 3 of which showed diffuse, strong nuclear expression, and 1 case displayed a complete loss of nuclear expression of p53, including invasive carcinoma and associated dysplasia, when present. Limited clinical follow-up was available, but 3 patients died of disease within 0.6, 2, and 7 months of diagnosis. We present the first series of undifferentiated carcinoma of the esophagus and gastroesophageal junction with this characteristic morphology associated with loss of SMARCA4 and/or SMARCA2 expression. This tumor type likely arises from dedifferentiation of a lower grade carcinoma in some cases, and Barrett esophagus and appears to be associated with an aggressive clinical course.

Malignant solitary fibrous tumour of the prostate: four cases emphasising significant histological and immunophenotypical overlap with sarcomatoid carcinoma.

Solitary fibrous tumour (SFT) is well-described in the urinary tract, but malignant examples are rare. We studied our experience with high grade malignant SFT of the prostate to address the degree of histological and immunophenotypical overlap with sarcomatoid carcinoma and prostatic stromal sarcoma. Four cases were identified from the surgical pathology consultation archives. All available H&E stained sections were reviewed. Immunostains for STAT6, CAM5.2, NKX3.1, PAX-8, GATA3, high molecular weight cytokeratin (34BE12), p40, and p63 were performed on available material. Each case was evaluated by three separate SFT prognostic risk models based on clinicopathological features, and for features of 'dedifferentiated SFT'. The patient's ages were 49, 55, 69, and 73 years. Three presented with symptoms of benign prostatic hyperplasia and one with haematuria. Tumour sizes were 5, 9, 13, and 13 cm. Mitotic rate ranged from 6 to 20 mitoses per 10 high power fields, and two cases showed abrupt transition from conventional SFT to areas with marked nuclear pleomorphism/anaplasia (i.e., 'de-differentiation'). Immunophenotypically, all four cases had strong and diffuse nuclear reactivity for STAT6. For other markers, three of three had both focal PR and GATA3 nuclear expression (up to 30% of cells). One case with 'dedifferentiated' features showed expression of multiple epithelial markers, including EMA (focal), high molecular weight cytokeratin (focal), p63, and p40. In summary, malignant SFT may rarely occur in the prostate and may closely mimic sarcomatoid carcinoma or prostatic stromal sarcoma, both histologically and immunophenotypically. Consideration of the diagnostic possibility of malignant SFT, recognition of unexpected GATA3 and PR expression, and utilisation of monoclonal STAT6 immunohistochemistry facilitate appropriate diagnosis at this unusual anatomical site.

Head-to-Head Comparison of p63 and p40 in Non-Neuroendocrine Carcinomas of the Tubal Gut.

OBJECTIVES.: With targeted agents, characterizing carcinomas of the gastrointestinal (GI) tract has become more important. We aim to determine the usefulness of p40 in classifying GI tract carcinomas. METHODS.: Seventy-five GI carcinomas including 28 squamous cell carcinomas (SCC), 2 adenosquamous carcinomas (ASCA), 21 poorly differentiated carcinomas (PDCA), and 24 adenocarcinomas (AdCA; control group) were stained for p40, p63, and CK5/6. Tumors were scored from 0 to 5 based on extent of staining and marked as positive (score >2) or negative. RESULTS.: p63 was positive in 100% of SCC/ASCA and 12.5% of AdCA. p40 was positive in 92.5% of SCC/ASCA and 4.1% of AdCA. In the PDCA subset, a panel including p63, p40, and MOC31 was the best way to accurately classify most cases. CONCLUSIONS.: p63 and CK5/6 are more sensitive but less specific than p40 for SCC/ASCA in GI carcinomas. In PDCA, a panel approach including p63, CK5/6, and p40 may be best in classifying these cases.

Smooth muscle tumors of the gastrointestinal tract: an analysis of prognostic features in 407 cases.

Smooth muscle tumors represent the second most common mural mesenchymal neoplasm in the gastrointestinal tract, but established criteria for prognostic assessment of these tumors are lacking. A large cohort of surgically resected intramural gastrointestinal smooth muscle tumors from 31 institutions was analyzed to identify potential prognostic features. Pathologic features were assessed by expert gastrointestinal and/or soft tissue pathologists at each center. Immunohistochemical confirmation was required. A total of 407 cases from the esophagus (n = 97, 24%), stomach (n = 180, 44%), small bowel (n = 74, 18%), and colorectum (n = 56, 14%) were identified. Patients ranged in age from 19 to 92 years (mean 55 years), with a slight female predominance (57%). Mean tumor size was 5.4 cm, with the largest tumor measuring 29 cm. Disease progression following surgery, defined as local recurrence, metastasis, or disease-related death, occurred in 56 patients (14%). Colorectal tumors were most likely to progress, followed by small bowel and gastric tumors. None of the esophageal tumors in this series progressed. Receiver operator characteristic analysis identified optimal cutoffs of 9.8 cm and 3 mitoses/5 mm2 for discriminating between progressive and non-progressive tumors. Histologic features strongly associated with progression by univariate analysis included moderate-to-severe atypia, high cellularity, abnormal differentiation (defined as differentiation not closely resembling that of normal smooth muscle), tumor necrosis, mucosal ulceration, lamina propria involvement, and serosal involvement (P < 0.0001 for all features). Age, sex, and margin status were not significantly associated with progression (P = 0.23, 0.82, and 0.07, respectively). A risk assessment table was created based on tumor site, size, and mitotic count, and Kaplan-Meier plots of progression-free survival for each subgroup revealed progression-based tiers. Based on our findings, it appears that nonesophageal gastrointestinal smooth muscle tumors measuring >10 cm and/or showing ≥3 mitoses/5 mm2 may behave aggressively, and therefore close clinical follow-up is recommended in these cases.

Murine model: maternal administration of stem cells for prevention of prematurity.

OBJECTIVE: Using a mouse model of intrauterine inflammation, we have demonstrated that exposure to inflammation induces preterm birth and perinatal brain injury. Mesenchymal stem cells (MSCs) have been shown to exhibit immunomodulatory effects in many inflammatory conditions. We hypothesized that treatment with human adipose tissue-derived MSCs may decrease the rate of preterm birth and perinatal brain injury through changes in antiinflammatory and regulatory milieu. STUDY DESIGN: A mouse model of intrauterine inflammation was used with the following groups: (1) control; (2) intrauterine inflammation (lipopolysaccharide); and (3) intrauterine lipopolysaccharide+intraperitoneal (MSCs). Preterm birth was investigated. Luminex multiplex enzyme-linked immunosorbent assays were performed for protein levels of cytokines in maternal and fetal compartments. Immunofluorescent staining was used to identify and localize MSCs and to examine microglial morphologic condition and neurotoxicity in perinatal brain. Behavioral testing was performed at postnatal day 5. RESULTS: Pretreatment with MSCs significantly decreased the rate of preterm birth by 21% compared with the lipopolysaccharide group (P<.01). Pretreatment was associated with increased interleukin-10 in maternal serum, increased interleukin-4 in placenta, decreased interleukin-6 in fetal brain (P<.05), decreased microglial activation (P<.05), and decreased fetal neurotoxicity (P<.05). These findings were associated with improved neurobehavioral testing at postnatal day 5 (P<.05). Injected MSCs were localized to placenta. CONCLUSION: Maternally administered MSCs appear to modulate maternal and fetal immune response to intrauterine inflammation in the model and decrease preterm birth, perinatal brain injury, and motor deficits in offspring mice.

Radiation-induced glioma following CyberKnife® treatment of metastatic renal cell carcinoma: a case report.

INTRODUCTION: Post-stereotactic radiation-induced neoplasms, although relatively rare, have raised the question of benefit regarding CyberKnife® treatments versus the risk of a secondary malignancy. The incidence of such neoplasms arising in the nervous system is thought to be low, given the paucity of case reports regarding such secondary lesions. CASE PRESENTATION: Here we describe a case of a 43-year-old Middle Eastern woman with primary clear cell renal cell carcinoma and a metastatic focus to the left brain parenchyma who presented with focal neurologic deficits. Following post-surgical stereotactic radiation in the region of the brain metastasis, the patient developed a secondary high-grade astrocytoma nearly 5 years after the initial treatment. CONCLUSION: Although the benefit of CyberKnife® radiotherapy treatments continues to outweigh the relatively low risk of a radiation-induced secondary malignancy, knowledge of such risks and a review of the literature are warranted.