Spindle cell variant of medullary thyroid carcinoma: a clinicopathologic study of four cases

Background Medullary thyroid carcinoma (MTC) is a malignant tumor derived from C cells. It accounts for about 10% of all thyroid malignancies. More than 14 histological variants have been described. Among them, spindle cell variant is extremely rare. Case presentation Here we describe 4 cases of spindle cell variant of MTC collected from 2012 to 2019. Ultrasound showed solid and hypoechoic nodules. Three patients underwent total thyroidectomy and regional lymph node dissection, and 1 patient underwent thyroid mass resection. Histologically, the tumors showed spindle shaped cells in bundles or interlaced arrangement, separated by hyalinised fibrous stroma that contained amyloid deposits. Immunohistochemistry showed that the tumor cells were positive for calcitonin, chromogranin A, synaptophysin, CD56, and TTF-1, but negative for other lineage-specific markers. Conclusions We report 4 rare cases of spindle cell variant of MTC. Due to its rarity and special morphology, the diagnosis of spindle cell variant MTC relies on its morphology and immunohistochemical markers to avoid misdiagnosis.

NetrinG1+ cancer-associated fibroblasts generate unique extracellular vesicles that support the survival of pancreatic cancer cells under nutritional stress

It is projected that, in 5 years, pancreatic cancer will become the second deadliest cancer in the United States. A unique aspect of pancreatic ductal adenocarcinoma (PDAC) is its stroma; rich in cancer-associated fibroblasts (CAFs) and a dense CAF-generated extracellular matrix (ECM). This fibrous stroma, known as desmoplasia, causes the collapse of local blood vessels rendering a nutrient-deprived milieu. Hence, PDAC cells are nurtured by local CAF-secreted products, which include, among others, CAF-generated small extracellular vesicles (sEVs). It is well-accepted that upon culturing functionally tumor-promoting CAFs under pathophysiological-relevant conditions (e.g., within self-produced ECM), these cells express NetrinG1 (NetG1) and sustain endosomal pools rich in active α5β1-integrin, traits indicative of poor patient survival. We herein report that NetG1+ CAFs generate sEVs that rescue PDAC cells from nutrient-deprived induced apoptosis. Two unique sEVs, NetG1+ and α5β1-integrin+, were uncovered. The former constitutes cargo of CAF-generated exomeres, and the latter is detected in classic exosomes. Proteomic and metabolomic analyses showed that the sEV-dependent PDAC survival is, at least in part, dictated by the cargo packaged within sEVs in a NetG1-dependent manner. Indeed, despite producing a similar number of vesicles, selected key proteins and metabolites (e.g., glutamine) were incorporated within the unique sEVs. Finally, we found that NetG1 and α5β1-integrin were detected in sEVs collected from plasma of PDAC patients, while their concomitant levels were significantly lower in plasma of sex/age-matched healthy donors. The discovery of these tumor-supporting CAF sEVs opens a new investigative avenue in tumor-stroma interactions and stroma staging detection.

Sclerosing Epithelioid Fibrosarcoma; A Case report and review of literature

Introduction/Objective Sclerosing Epithelioid Fibrosarcoma (SEF) is an unusual, rare clinically aggressive form of soft tissue sarcoma. It is characterized by a slow evolution, with local recurrences and late metastases that are mainly pulmonary and pleural in about 80% of cases. SEF has distinctive morphology and occurs most commonly in deep soft tissue of adult extremities. Lesions involving the head and neck region are uncommon and rare intraosseously in oral cavity. Methods/Case Report Herein we report a case of a 52-year-old male who presented with a symptomatic radiolucent lesion at apex #18, with clinical impression of periapical granuloma. The patient did present with pain associated with lower left quadrant #18 area, for several days to pressure and hot temperature. A periapical radiograph revealed a large ill-defined radiolucent area at apex of resorbing roots #18. The patient’s medical history was significant with history of cancer diagnosis of sclerosing epithelioid fibrosarcoma of skull treated by chemotherapy and radiation. Microscopic examination of the specimen revealed a multi-fragmented specimen consisting of numerous fragments and islands of highly cellular, basophilic bone and osteoid surrounded by loose fibrous stroma which contains large lobules and islands of round to oval cells, with distinct cell borders and faintly granular eosinophilic cytoplasm. Separate islands of tumor cells surround large islands of necrosis with the background stroma appearing as hyalinized and eosinophilic with the basaloid cells demonstrating smudge and crush artifact. Peripherally, spindled cells are noted and faint areas of eosinophilic osteoid within the eosinophilic background stroma. Lesional cells are MUC4 strong, diffusely positive and strongly positive for INI-1. CD43, CD20, PAX-5, CD3, Desmin, CD34, S100, CD99, AE1/3 and SMA are interpreted to be negative. A diagnosis of metastatic sclerosing epithelioid fibrosarcoma was made, with correlation with the primary lesion was recommended. Results (if a Case Study enter NA) N/A Conclusion The clinical and histological findings of our case correlate with the diagnostic criteria of sclerosing epithelioid fibrosarcoma. Despite its microscopic features can create diagnostic difficulties, in that SEF can resemble a variety of benign and pseudosarcomatous as well as malignant lesions, our case diagnosis was confirmed by morphology and MUC4 diffuse strong reactivity and negativity for other markers.

Ossifying Fibroma; A Case report and review of literature

Introduction/Objective Ossifying fibroma (OF) is a rare, benign, true neoplasm with growth potential, with the mandible involved more often than the maxilla. There is female predilection in the third and fourth decades of life, with the most common site being the premolar and molar area of the mandible. These lesions are characterized by the replacement of endogenous bone with a highly cellular fibrous neoplasm containing varied amounts of bony trabeculae, and/or cementum-like spherules. Radiographically they present as well defined, unilocular, most are mixed lucent, opaque, some with sclerotic border and root divergence may be seen. Histologically most of the lesions are not encapsulated but are well demarcated from the adjacent bone. Thus radiographic, surgical and histological findings help distinguish OF from other benign fibro-osseous lesions such as fibrous dysplasia and cemento-osseous dysplasia. Distinguishing an accurate diagnosis between the above fibro-osseous neoplasms becomes significant as prognosis and treatment differ. Methods/Case Report Herein we report a case of a 59-year-old female who presented with a symptomatic mandibular lesion that radiographically illustrated a midline well-circumscribed expansile mass of the mandibular symphysis with a sclerotic margin and ground-glass internal matrix measuring 3.1 x 4.9 x 3.9 cm, favored to represent pagetoid changes more likely than neoplastic process. Microscopic examination revealed numerous variably sized islands of ossification within a hypercellular fibrous stroma. Based on the clinical, radiographic and histologic findings, a diagnosis of benign fibro-osseous lesion, favor ossifying fibroma was given. Results (if a Case Study enter NA) NA Conclusion Microscopic examination, as in our case, can resemble a variety of benign fibro-osseous neoplasms. Radiographic and clinical correlation, along with microscopic evaluation, help solidify the accurate diagnosis.

Hepatobiliary phase signal intensity: A potential method of diagnosing HCC with atypical imaging features among LR-M observations

Herein, we assessed whether hepatobiliary phase (HBP) signal intensity (SI) can be used to differentiate HCC and non-HCC malignancies within LR-M observations. 106 LR-M patients based on LI-RADS v2018 who underwent gadoxetate-disodium magnetic resonance imaging and surgery from January 2009 to December 2018 were included. SI of LR-M observation on HBP was analyzed by two radiologists and categorized into dark, low and iso-to-high groups. Tumor was classified as dark when more than 50% of tumor showed hypointensity compared to spleen, as low when more than 50% of tumor showed hyperintensity compared to spleen but hypointensity compared to liver parenchyma, and as iso-to-high if there was even a focal iso-intensity or hyperintensity compared to liver parenchyma. Analysis of clinicopathological factors and association between imaging and histology was performed. Out of 106 LR-M, 42 (40%) were showed dark, 61 (58%) showed low, and 3 (3%) showed iso-to-high SI in HBP. Three iso-to-high SI LR-M were HCCs (P = 0.060) and their major histologic differentiation was Edmondson grade 1 (P = 0.001). 43 out of 61 (71%) low SI LR-M were iCCA or cHCC-CCA (P = 0.002). Inter-reader agreement of HBP SI classification was excellent, with a kappa coefficient of 0.872. LR-M with iso-to-high SI in HBP is prone to being HCC while LR-M with low SI in HBP is prone to being tumor with fibrous stroma such as iCCA and cHCC-CCA. Classification of LR-M based on HBP SI may be a helpful method of differentiating HCC from non-HCC malignancies.

Mechanical Pressure Driving Proteoglycan Expression in Mammographic Density: a Self-perpetuating Cycle?

Regions of high mammographic density (MD) in the breast are characterised by a proteoglycan (PG)-rich fibrous stroma, where PGs mediate aligned collagen fibrils to control tissue stiffness and hence the response to mechanical forces. Literature is accumulating to support the notion that mechanical stiffness may drive PG synthesis in the breast contributing to MD. We review emerging patterns in MD and other biological settings, of a positive feedback cycle of force promoting PG synthesis, such as in articular cartilage, due to increased pressure on weight bearing joints. Furthermore, we present evidence to suggest a pro-tumorigenic effect of increased mechanical force on epithelial cells in contexts where PG-mediated, aligned collagen fibrous tissue abounds, with implications for breast cancer development attributable to high MD. Finally, we summarise means through which this positive feedback mechanism of PG synthesis may be intercepted to reduce mechanical force within tissues and thus reduce disease burden.

Large Brunner’s Gland Hyperplasia with Bleeding: A Case Report

We report a rare case of a large Brunner’s gland hyperplasia (BGH) with severe anemia. A 33-year-old woman was transferred to our hospital with anemia and a duodenal mass. She had a 2-week history of melena and mild shortness of breath. Her hemoglobin level was 4.9 g/dl, and she required a blood transfusion. Abdominal computed tomography revealed a 7 cm tumor in the descending duodenum, and duodenoscopy revealed a polyp-like tumor with an ulcer at the duodenal bulb. We decided to perform surgery to prevent further bleeding. Intraoperatively, the tumor stalk was located at the anterior wall of the duodenal bulb; the ampulla was not involved, and we resected the tumor with the wall of the duodenal bulb. The resected tumor measured 7.0 × 4.0 × 2.3 cm , and pathologically, the tumor consisted of proliferated Brunner’s glands in a small amount of fibrous stroma. The histological diagnosis was BGH with no malignancy. Most cases of BGH are benign and asymptomatic; however, it is important to be aware that some patients have severe anemia, gastrointestinal obstruction, or malignant potential.

CRTC1–SS18 Fusion Sarcoma With Aberrant Anaplastic Lymphoma Kinase Expression

Undifferentiated small round cell sarcoma (USRCS) represents a highly heterogeneous group of tumors. A variety of specific gene fusions of USRCS have been reported, including CIC–FOXO4, CIC–NUTM1, BCOR–MAML3, and ZC3H7B–BCOR. Here we report a case of sarcoma harboring a rare recurrent CRTC1–SS18 gene fusion, which was considered as USRCS previously. This sarcoma was composed of nests of small round cells encapsulated in a fibrous stroma. Foci of necrosis and hemorrhage were observed in the tumor. Immunohistochemistry for anaplastic lymphoma kinase showed diffuse positivity. RNA-seq results revealed a chromosomal translocation of CRTC1 gene exon 1 on chromosome 19 with SS18 gene exon 2 on chromosome 18. Thereafter, fluorescence in-situ hybridization confirmed the presence of SS18 gene and CRTC1 gene break-apart, which manifested as the splitting of red and green signals into 2 parts. A previous study showed that CRTC1–SS18 fusion sarcoma and EWSR1–CREB1 fusion angiomatoid fibrous histiocytoma were clustered close in the expression profile. However, whether CRTC1–SS18 fusion sarcomas represent a high malignancy has been a matter of debate. Our study is a worthy addition to the series of rare rearrangements associated with sarcomas and may be of therapeutic relevance.

Ductal Plate Malformations in Captive Snakes

Ductal plate malformations are abnormalities in the liver that arise from inappropriate or incomplete remodeling of the embryologic ductal plate. Various types of ductal plate malformations are reported in the human and veterinary literature, most commonly affecting domestic mammalian species but also fish. We investigated the occurrence and described the histopathologic features of ductal plate malformations in captive snakes. Malformations were identified in 18 snakes: 10 colubrids, 6 vipers, and 2 boids. There was no sex predilection, and the mean age was 17 years. The majority of lesions were incidental with most snakes having one or more comorbidities, most commonly neoplasia or systemic inflammation, that resulted in natural death or euthanasia. Ductal plate malformations in all livers were broadly characterized by a well-demarcated nodule of irregular bile ducts embedded within a varying amount of fibrous stroma. Malformations were further categorized based on the amount of fibrous stroma and dilation of the bile ducts as von Meyenburg complexes, cystic liver disease, and/or an intermediate hybrid subtype representative of cysts arising within von Meyenburg complexes. Histochemical and immunohistochemical staining, including Gomori’s trichome and pan-cytokeratin, respectively, were applied on select cases to confirm histologic features. Malignant transformation was not identified within this population.

Diagnostic and pathogenic features of calcifying pseudoneoplasm of the neuraxis

Calcifying pseudoneoplasm of the neuraxis (CAPNON) is a rare tumefactive lesion with unclear pathogenesis. It is diagnosed by pathological findings of the typical histological features that include granular amorphous cores with palisading spindle to epithelioid cells, variable fibrous stroma, foreign-body reaction with giant cells, and calcification/ossification occasionally with psammoma bodies. However, its histopathology may be variable and currently immunohistochemistry plays a limited role in its diagnosis and understanding the pathogenesis. In this study, we examined 6 cases of CAPNONs including 3 intracranial and 3 spinal epidural lesions (age range: 59–69 years; 3 males and 3 females). Immunohistochemistry revealed that all CAPNON cores contain abundant positive deposits of neurofilament protein (NFP), which was supported by electron microscopy finding of filaments (8–13 nm in diameter). In comparison, no NFP positivity was found in 5 psammomatous/metaplastic meningiomas or 7 intervertebral tissue lesions with calcification/ossification. In addition, CAPNON cellular areas showed variable numbers of CD8+ cytotoxic T-cells with less CD4+ T-cells and a decreased ratio of CD4/CD8+ cells, versus the intervertebral tissue lesions without CD8+ or CD4+ cells. Our findings suggest that NFP may be a principal constituent of CAPNONs, and thus involved in the pathogenesis of CAPNON. Given the decreased CD4/CD8 ratio, the pathogenic process of CAPNON is possibly immune- mediated.LEARNING OBJECTIVESThe presentation will enable the learner to: 1.Discuss histopathological features of calcifying pseudoneoplasm of the neuraxis (CAPNON) with variation of non-core components.2.Explore diagnostic and pathogenic roles of immunohistochemical markers including neurofilament protein and CD4/CD8 in CAPNON.