Positivity For Smooth Muscle Actin Research Articles

Endobronchial Leiomyoma, an Unusual Tumor in an Unusual Site

Abstract Leiomyomas are benign smooth muscle tumors most commonly seen in the uterus occasionally in the gastrointestinal tract. Pulmonary localization is extremely rare with the incidence of <2%. We report the case of a 22-year-old nonsmoking female who presented with left-sided chest pain and streaky hemoptysis. Chest xray showed left lingular lobe and lower lobe collapse. Contrast-enhanced computed tomography showed endobronchial obstruction in the left main bronchus. Debulking was done with electrocautery snare. Histopathological examination showed spindle-shaped cells with eosinophilic cytoplasm. Immunohistochemistry showed smooth muscle actin positivity suggestive of leiomyoma. The patient is under follow-up without any complication and recurrence.

Antral plexiform fibromyxoma: case report of a rare mesenchymal neoplasm

Plexiform fibromyxoma (PF) is a rare mesenchymal neoplasm of the stomach usually arising in the gastric antrum, and its main differential diagnosis is gastrointestinal stromal tumor. Most common symptoms are hematemesis, anemia. Immunohistochemically, positivity for smooth muscle actin (SMA) and vimentin suggests the diagnosis of PF. We report the case of a 56-year-old female patient with a 30- day history of nausea at presentation 4 years ago. Gastroscopy at that time revealed a subepithelial lesion (SEL) in the gastric antrum, measuring approximately 20 mm in diameter, with leakage of serous fluid after biopsy. Histopathology showed only an inflammatory process. Follow-up gastroscopies were performed 24, 36, and 48 months later, with surveillance biopsy at each follow-up. The last gastroscopies showed changes in lesion appearance, reduction in size, and absence of fluid leakage. Histopathology showed bland spindle cell proliferation, with a vaguely plexiform/multinodular pattern, in a fibromyxoid stroma with an arborizing capillary network without mitoses. The tumor cells were positive for SMA and negative for DOG1, CD117, CD34, S100, desmin, EMA, CD10, calponin, and beta-catenin. The choice of treatment and follow-up depends on the SEL features, but because no cases of malignancy or metastatic disease have previously been reported, the patient chose a conservative approach.

Lineage and geometry of MRI‐visible perivenous and periarterial spaces in white matter confirmed on immunohistochemical microscopy

AbstractBackgroundMRI‐visible perivascular spaces (mrPVS) in the brain, typically found in white matter and assumed to be pathologically enlarged though historically considered a benign finding, have been more recently associated with normal aging as well as with various disease states, including traumatic brain injury, sleep apnea, Alzheimer’s Disease (AD), Parkinson’s Disease, and cerebral amyloid angiopathy. One putative cause for their pathological enlargement has been damage to the parenchyma surrounding the PVS, bounded by the astrocytic endfoot, caused by an increase in vascular pressure or pulsatility. Arteries are more pulsatile than veins, and thus it is expected that mrPVS, presumed to be enlarged, will be predominately around arteries. This pre and post mortem MRI + immunohistochemistry (IHC) study sought to clarify the lineage and spatial distribution of PVS visible at the resolution of MRI in aged individuals who were cognitively normal (C), mildly cognitively impaired (MCI), had clinical signs of dementia and mixed AD and vascular disease at pathology (AD/VD), and had pathology‐confirmed AD only (AD).MethodDetailed imaging and IHC acquisition, as well as MRI and IHC processing and registration methods, can be found at [https://pubmed.ncbi.nlm.nih.gov/36343095/ and https://pubmed.ncbi.nlm.nih.gov/36054513/]. Each MRI was inspected for PVS by an experienced rater (JH) and trichrome and smooth muscle actin (SMA) IHC of the corresponding vessels were judged to be arteries or veins based on SMA positivity and morphology (DLS).Result35 mrPVS over 19 subjects’ post mortem MRIs were unequivocally identified on trichrome and SMA. Of these, 23 surrounded arteries (SMA+, Fig. 1), and 12 surrounded veins (faint/thin/uneven SMA, Fig. 2). Mean distance (range) to the cortical ribbon from mrPVS surrounding arteries and veins were 2.8mm[0‐8mm] and 5.4mm[2‐14mm], respectively.ConclusionPVS large enough to be visible on MRI are more frequently arterial if nearer the cortical ribbon; mrPVS nearer the ventricle are more likely to be collecting veins. As collecting veins nearer the ventricles and arterioles in cortex tend to have higher pulse pressures, this finding is congruent with the hypothesis that PVS may enlarge as a result of higher vascular pressures common in older age and cerebrovascular disease.

Lineage and geometry of MRI‐visible perivenous and periarterial spaces in white matter confirmed on immunohistochemical microscopy

AbstractBackgroundMRI‐visible perivascular spaces (mrPVS) in the brain, typically found in white matter and assumed to be pathologically enlarged though historically considered a benign finding, have been more recently associated with normal aging as well as with various disease states, including traumatic brain injury, sleep apnea, Alzheimer’s Disease (AD), Parkinson’s Disease, and cerebral amyloid angiopathy. One putative cause for their pathological enlargement has been damage to the parenchyma surrounding the PVS, bounded by the astrocytic endfoot, caused by an increase in vascular pressure or pulsatility. Arteries are more pulsatile than veins, and thus it is expected that mrPVS, presumed to be enlarged, will be predominately around arteries. This pre and post mortem MRI + immunohistochemistry (IHC) study sought to clarify the lineage and spatial distribution of PVS visible at the resolution of MRI in aged individuals who were cognitively normal (C), mildly cognitively impaired (MCI), had clinical signs of dementia and mixed AD and vascular disease at pathology (AD/VD), and had pathology‐confirmed AD only (AD).MethodDetailed imaging and IHC acquisition, as well as MRI and IHC processing and registration methods, can be found at [https://pubmed.ncbi.nlm.nih.gov/36343095/ and https://pubmed.ncbi.nlm.nih.gov/36054513/]. Each MRI was inspected for PVS by an experienced rater (JH) and trichrome and smooth muscle actin (SMA) IHC of the corresponding vessels were judged to be arteries or veins based on SMA positivity and morphology (DLS).Result35 mrPVS over 19 subjects’ post mortem MRIs were unequivocally identified on trichrome and SMA. Of these, 23 surrounded arteries (SMA+, Fig. 1), and 12 surrounded veins (faint/thin/uneven SMA, Fig. 2). Mean distance (range) to the cortical ribbon from mrPVS surrounding arteries and veins were 2.8mm[0‐8mm] and 5.4mm[2‐14mm], respectively.ConclusionPVS large enough to be visible on MRI are more frequently arterial if nearer the cortical ribbon; mrPVS nearer the ventricle are more likely to be collecting veins. As collecting veins nearer the ventricles and arterioles in cortex tend to have higher pulse pressures, this finding is congruent with the hypothesis that PVS may enlarge as a result of higher vascular pressures common in older age and cerebrovascular disease.

LOW-GRADE MYOFIBROBLASTIC SARCOMA OF THE ORAL CAVITY

Low-grade myofibroblastic sarcoma (LGMS) represents a distinct atypical myofibroblastic tumor of deep soft tissues, with a head and neck predilection. It has a variety of appearances, from fasciitis-like or fibromatosis-like to fibrosarcoma-like. Here, a series of four cases from two different institutions is shown, represented by 2 men and 2 women presenting a nodular lesion, with equal distribution in maxilla and mandibula. Microscopically, all cases showed neoplasms formed by oval to spindle cells in a fibrous stroma with myxoid and dense areas, some atypical mitoses, and prominent nucleoli. These findings suggested a mesenchymal tumor. An immunohistochemical panel was performed, which showed positivity for smooth muscle actin (3 of 4 cases), HHF35 (2 of 4 cases), β-catenin (3 of 3 cases), calponin (2 of 4 cases), and Ki-67 (range 5-40%). H-Caldesmon was negative for all cases, demonstrating myofibroblastic and smooth muscle differentiation. The diagnosis of LGMS was confirmed in all cases. Low-grade myofibroblastic sarcoma (LGMS) represents a distinct atypical myofibroblastic tumor of deep soft tissues, with a head and neck predilection. It has a variety of appearances, from fasciitis-like or fibromatosis-like to fibrosarcoma-like. Here, a series of four cases from two different institutions is shown, represented by 2 men and 2 women presenting a nodular lesion, with equal distribution in maxilla and mandibula. Microscopically, all cases showed neoplasms formed by oval to spindle cells in a fibrous stroma with myxoid and dense areas, some atypical mitoses, and prominent nucleoli. These findings suggested a mesenchymal tumor. An immunohistochemical panel was performed, which showed positivity for smooth muscle actin (3 of 4 cases), HHF35 (2 of 4 cases), β-catenin (3 of 3 cases), calponin (2 of 4 cases), and Ki-67 (range 5-40%). H-Caldesmon was negative for all cases, demonstrating myofibroblastic and smooth muscle differentiation. The diagnosis of LGMS was confirmed in all cases.

Characterizing the role of pulmonary veins in pulmonary hypertension

Pulmonary veins (PVs) transport oxygenated blood from lungs back to the heart. Small PVs can play a crucial role in the pathogenesis of pulmonary hypertension. Studies have also shown PV remodeling in pulmonary hypertension and heart failure. However, unlike pulmonary arteries (PAs), which have been a major focus of pulmonary vascular studies, the signaling mechanisms in PVs have not been investigated under normal conditions and in pulmonary hypertension. We hypothesized that the vascular wall composition and cellular signaling mechanisms in PVs are distinct from PAs. We imaged 4th order PVs (~ 50 mm) from C57BL6 mice using spinning disk confocal imaging along the z-axis. In direct contrast to PAs, where a single endothelial cell (EC) layer is surrounded by alpha actin-positive smooth muscle cells (SMCs), PV walls did not show SMCs. Cardiac troponin C staining of PVs identified cardiac myocyte-like (CML) cells with striations surrounding the EC layer. The CML layer was not observed in small PAs, vena cava, and mesenteric veins. Confocal calcium imaging showed spontaneous calcium signals in CML cells from PVs that were inhibited by ryanodine (1 mM), a ryanodine receptor inhibitor. Cannulated PVs in pressure myography experiments showed spontaneous pulsatile constrictions, which were also inhibited by ryanodine. Collectively, our results suggest that ryanodine receptor calcium signals in CML cells underlie spontaneous contractions in small PVs. Our findings also indicate that signaling mechanisms in CML cells could be potential targets for therapy in pulmonary hypertension. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

The capillary lobule variant of radiation-associated angiosarcoma in the setting of breast cancer: A diagnostic pitfall.

Post-radiation angiosarcoma is an iatrogenic event seen in the setting of breast cancer treatment. Histopathologically, there are morphologic variants of angiosarcoma that mimic benign entities, including the capillary lobule variant of post-radiation angiosarcoma. We present the largest case series to date of this histopathologic variant of post-radiation angiosarcoma. Cases of the capillary lobule variant of post-radiation angiosarcoma from institutional/consultation archives from 2008 to June 2022 were reviewed. For inclusion, tumors had to occur in irradiated skin and exhibit a multi-lobular proliferation of tightly packed capillary-like vessels, as previously described in this variant. Prior ancillary studies were also reviewed. Eight cases met the criteria. All occurred in women treated with radiation for breast cancer (median age 75 years). All cases had similar findings, including a multi-lobular proliferation of tightly packed vessels, infiltrative cords, and atypical single endothelial cells. A conventional angiosarcoma pattern was also seen in five cases. All cases tested were positive for vascular markers (CD31, CD34, and/or ERG) and MYC. MYC amplification was shown by FISH in all cases tested. Smooth muscle actin (SMA) was positive in pericytes in the capillary lobules in all five cases tested and areas of conventional angiosarcoma in two of three cases. The capillary lobule variant of angiosarcoma is a rare and therefore potentially under-recognized variant of post-radiation angiosarcoma. The lobular architecture and SMA positivity may mimic benign vascular proliferations. Careful attention to histopathologic features and ancillary tests may facilitate accurate diagnosis.

S3595 Gastric Glomus Tumors: Silent Until Ulcerated

Introduction: Glomus tumors are rare and mostly benign mesenchymal neoplasms comprising fewer than 2% of all soft tissue tumors. They arise from the modified smooth muscle cells (glomus cells) of the glomus body, an arteriovenous shunt typically found in peripheral soft tissue of the extremities. Rarely, glomus tumors can occur in the gastrointestinal (GI) tract, where they arise from the submucosa or muscularis propria. We present two interesting cases of gastric glomus tumor (GGT) with different clinical outcomes. Case Description/Methods: A 46-year-old female presented with shortness of breath and fatigue for 3 months. Labs showed iron deficiency anemia with a hemoglobin of 4.4 gm/dl. Esophagogastroduodenoscopy (EGD) revealed a large, ulcerated, partially circumferential mass in the gastric (Figure 1A, 1B) Imaging showed a solid 7.8 cm mass in the gastric antrum with multiple hepatic metastases. Gastric biopsy showed glomus tumor, with a positive smooth muscle actin (SMA) stain and abundant background necrosis. Liver biopsy also confirmed metastasis of the glomus tumor. Patient is currently undergoing chemotherapy to downsize the primary tumor before surgical intervention. A 72-year-old female with a history of breast cancer was admitted with hematemesis and melena. EGD revealed a large submucosal ulcerated gastric mass with signs of bleeding. Endoscopic ultrasound (EUS) showed the mass was arising from the muscularis propria, in the antrum of the stomach (Figure 2A, 2B) Fine needle aspiration was performed which expressed only synaptophysin (Syn), suggestive of gastric neuroendocrine tumor. Patient underwent an exploratory laparotomy and distal gastrectomy for continued GI bleeding. The tumor was sent for surgical pathology, which expressed both smooth muscle actin and Syn, confirming glomus tumor. The patient was stable following gastrectomy. Discussion: GGTs account for approximately 1% of all GI mesenchymal tumors and are difficult to differentiate from other richly vascularized tumors, such as gastrointestinal stromal tumor (GIST). The definitive diagnosis relies on EGD, histopathologic examination with immunohistochemical staining and EUS-guided fine-needle aspiration. Glomus tumor cells stain positive for SMA and vimentin, while Syn and CD34 can be positive in some cases. Surgical resection is the treatment of choice and offers a favourable prognosis. Metastatic spread as seen in one of our cases is extremely rare. There are no standard of care chemotherapeutic regimens for treatment of GGTs.Figure 1.: Two gastric glomus tumors seen on esophagogastroduodenoscopy (EGD) and endoscopic ultrasound (EUS).

S2222 A Rare Case of Primary Leiomyosarcoma of the Colon versus Metastasis

Introduction: Leiomyosarcoma (LMS) is an aggressive soft tissue tumor that is rarely found in the gastrointestinal (GI) tract. Commonly misdiagnosed as a gastrointestinal stromal tumor (GIST), LMS incidence is now more accurately identified and rarer than previously thought due to advances in immunohistochemical (IHC) staining over the last 20 years. LMS can be distinguished from GIST by its distinctive IHC staining positive for smooth muscle actin (SMA) and desmin and negative for markers CD117, CD34, DOG1. We present the case of a patient who was found to have a colonic polyp with increased mitotic activity and ultimately diagnosed with metastatic LMS. Case Description/Methods: A 72-year-old woman with history of uterine fibroids post hysterectomy underwent a routine screening colonoscopy. She was found to have a diminutive polyp in the hepatic flexure identified as a smooth muscle neoplasm with increased mitotic activity. A follow up colonoscopy 6 months later also revealed a polyp with smooth muscle neoplasm with high mitotic activity (2-3 per one high-power field). IHC staining on both polyps showed positive SMA and negative GIST markers (Figure). Proliferation index (Ki-67) was 20%. The differential diagnosis was rare primary leiomyosarcoma of colon versus metastasis. Abdominal and pelvis imaging with CT and MRI was nonrevealing. Three months after the follow up colonoscopy, the patient had ongoing neck pain and was found to have a lung mass and bone metastasis identified as LMS. She received multiple chemotherapy agents and then anastrozole after tumor hormone staining was estrogen receptor positive. Discussion: We present an interesting case of metastatic leiomyosarcoma involving colon, lung, and bone with unknown primary. Because LMS spreads hematogenously, it is difficult to identify the primary LMS lesion. Her history of uterine leiomyoma is another potential source. Initial expert consultation indicated primary smooth muscle neoplasm of colon with 40% chance of progression. It became clear due to the discovery of additional foci of metastasis that the colonic lesions were also metastasis. We share this case to highlight a constellation of overlapping characteristics of mesenchymal tumors in the GI tract. The distinction among LMS and GIST with proper IHC staining is extremely important since treatment is vastly different. If the diagnosis is not immediately clear, like in our case, expert pathology evaluation, a multidisciplinary approach, and close endoscopic follow up are of the upmost importance.Figure 1.: High magnification pathology slides. (A) Mitotic figure identified by arrow. (B) IHC staining confirms the smooth muscle nature of this neoplasm as tumor cell are positive for SMA.

CD56 and smooth muscle actin immunoreactivity in basal cell carcinomas: Are they indicators of differentiation or do they hold a diagnostic use?

Basal cell carcinoma (BCC) is the most common cutaneous malignancy and may show various differentiations. The possible pluripotent stem cell lineage of BCCs, whose origins are controversial today, is thought to be the main reason for the different morphologies. The aim of the study is to evaluate the expression of some neuroendocrine and smooth muscle markers of differentiation in BCCs and investigate the relationship between histopathologic subtypes and recurrence. A total of 128 cases diagnosed as BCC in our center were included. Immunohistochemical studies of CD56, synaptophysin, chromogranin-A, smooth muscle actin (SMA), desmin, caldesmon, and Ki67 were applied. CD56, chromogranin-A, and synaptophysin immunoreactivity were detected in 77.3%, 13.3%, and 0.8% of the cases, respectively. 78.1% showed SMA positivity while no tumor expressed desmin or caldesmon. A correlation between histopathologic recurrence risk groups and CD56 expression was found (p < 0.05). CD56 and SMA immunoreactivity is present in the majority of BCCs. However, the available findings do not support neuroendocrine or smooth muscle differentiation. CD56 antigen can be used for prognostic purposes in detecting high recurrence risk tumors. After the investigation of the expression rates of these two antigens in different cutaneous tumors, it may be appropriate to use them for diagnostic purposes in BCCs.

Divergence of acetate uptake in proinflammatory and inflammation-resolving macrophages: implications for imaging atherosclerosis

BackgroundMetabolic divergence of macrophages polarized into different phenotypes represents a mechanistically relevant target for non-invasive characterization of atherosclerotic plaques using positron emission tomography (PET). Carbon-11 (11C)-labeled acetate is a clinically available tracer which accumulates in atherosclerotic plaques, but its biological and clinical correlates in atherosclerosis are undefined. Methods and resultsHistological correlates of 14C-acetate uptake were determined in brachiocephalic arteries of western diet-fed apoE−/− mice. The effect of polarizing stimuli on 14C-acetate uptake was determined by proinflammatory (interferon-γ + lipopolysaccharide) vs inflammation-resolving (interleukin-4) stimulation of murine macrophages and human carotid endarterectomy specimens over 2 days. 14C-acetate accumulated in atherosclerotic regions of arteries. CD68-positive monocytes/macrophages vs smooth muscle actin-positive smooth muscle cells were the dominant cells in regions with high vs low 14C-acetate uptake. 14C-acetate uptake progressively decreased in proinflammatory macrophages to 25.9 ± 4.5% of baseline (P < .001). A delayed increase in 14C-acetate uptake was induced in inflammation-resolving macrophages, reaching to 164.1 ± 21.4% (P < .01) of baseline. Consistently, stimulation of endarterectomy specimens with interferon-γ + lipopolysaccharide decreased 14C-acetate uptake to 66.5 ± 14.5%, while interleukin-4 increased 14C-acetate uptake to 151.5 ± 25.8% compared to non-stimulated plaques (P < .05). ConclusionsAcetate uptake by macrophages diverges upon proinflammatory and inflammation-resolving stimulation, which may be exploited for immunometabolic characterization of atherosclerosis.

Histopathological analysis of residual lens cells in capsular opacities after cataract surgery using objective software

Purpose:Remnant lens epithelial cells (LECs) within the capsular bag (CB) undergo epithelial-to-mesenchymal transition (EMT) and acquire a myofibroblast phenotype, depositing extracellular matrix (ECM) components, leading to posterior capsular opacification (PCO). This study histopathologically analyzes the LEC-to-myofibroblast transition and de novo ECM component deposition (i.e., smooth muscle actin (SMA) and fibronectin (FN) expression) and determines the intraocular lens (IOL) and patient factors associated with these changes.Methods:In total, 190 CBs with IOLs were removed from donor eyes. Digital images were obtained, and PCO was graded using published software (ADOS, Medical Parachute). Automated immunohistochemistry was performed using anti-SMA to detect EMT and anti-FN to document ECM remodeling. Slides were digitized and analyzed using the Positive Pixel Count v9 algorithm. Linear regression and Poisson regression were performed (P < 0.05).Results:SMA positive expression decreased as the time of IOL implantation increased (P < 0.0001). Positivity of SMA and FN demonstrated a positive correlation (P = 0.0002). Controlling for confounding factors in Poisson regression, hydrophobic and hydrophilic materials showed higher FN and SMA expression when compared to silicone material lenses (FN; P = 0.018; P < 0.0001, SMA; P = 0.001; P = 0.003, respectively). The square optic design had 29% higher SMA positivity compared to the opti-edge design (P = 0.042). One-piece haptic lenses had higher SMA expression compared to three-piece haptic (P = 0.042). A higher risk of expression of SMA and FN was seen in patients with a history of smoking, hypertension, and glaucoma (P < 0.05).Conclusion:This study demonstrated that SMA and FN expression is different according to IOL design and patient factors, thus indicating that LEC changes depend on lens biocompatibility. Therefore, by analyzing the histopathological composition of PCO by using LECs, further insight into the characteristics of IOLs that are important for biocompatibility can be ascertained.

Overexpression of Human Estrogen Biosynthetic Enzyme Hydroxysteroid (17beta) Dehydrogenase Type 1 Induces Adenomyosis-like Phenotype in Transgenic Mice.

Hydroxysteroid (17beta) dehydrogenase type 1 (HSD17B1) is an enzyme that converts estrone to estradiol, while adenomyosis is an estrogen-dependent disease with poorly understood pathophysiology. In the present study, we show that mice universally over-expressing human estrogen biosynthetic enzyme HSD17B1 (HSD17B1TG mice) present with adenomyosis phenotype, characterized by histological and molecular evaluation. The first adenomyotic changes with endometrial glands partially or fully infiltrated into the myometrium appeared at the age of 5.5 months in HSD17B1TG females and became more prominent with increasing age. Preceding the phenotype, increased myometrial smooth muscle actin positivity and increased amount of glandular myofibroblast cells were observed in HSD17B1TG uteri. This was accompanied by transcriptomic upregulation of inflammatory and estrogen signaling pathways. Further, the genes upregulated in the HSD17B1TG uterus were enriched with genes previously observed to be induced in the human adenomyotic uterus, including several genes of the NFKB pathway. A 6-week-long HSD17B1 inhibitor treatment reduced the occurrence of the adenomyotic changes by 5-fold, whereas no effect was observed in the vehicle-treated HSD17B1TG mice, suggesting that estrogen is the main upstream regulator of adenomyosis-induced uterine signaling pathways. HSD17B1 is considered as a promising drug target to inhibit estrogen-dependent growth of endometrial disorders. The present data indicate that HSD17B1 over-expression in TG mice results in adenomyotic changes reversed by HSD17B1 inhibitor treatment and HSD17B1 is, thus, a potential novel drug target for adenomyosis.

S3118 Through Thick and Thick: An Unusual Presentation of Gastric Amyloidosis

Introduction: GI amyloidosis (GIA) is relatively rare constitutes 3% to 8% of patients with systemic amyloidosis. A mere 1% of primary gastric amyloidosis were found to be symptomatic. We elaborate on an unusual presentation of GIA where nausea and vomiting were the only symptoms. Case Description/Methods: A 55-year-old male presents with nausea and vomiting for the past 3 weeks, found to have acute normocytic anemia (hemoglobin 6.1), leukocytosis (16K/mm3), and acute renal failure. Upper endoscopy revealed diffuse gastric wall thickening and subsequent endoscopic ultrasound revealed diffuse gastric wall thickening up to deep mucosa, up to 1.1cm in the cardia, fundus, body, and antrum. Biopsies revealed pale eosinophilic material, orangeophilic on congo red stain, and apple green birefringent on polarization microscopy consistent with AL (kappa)-type amyloidosis. Bone marrow biopsy showed hypercellular bone marrow (60%) with 6% plasma cells, chemotherapy with cyclophosphamide plus daratumumab was initiated. Free light chain levels improved to 50% within 1 month and he continues therapy for hematologic remission. Discussion: GIA is defined as the presence of GI symptoms with direct tissue biopsy with positive staining of amyloid by Congo red. Those with AL amyloidosis have median survival times of 15.84 months for those without GIA, and 7.95 months for those with GIA. Our patient with nonspecific symptoms, had lab and endoscopic evaluation; biopsy is necessary to clinch such a diagnosis.Figure 1.: Image 1: CT image demonstrating gastric mass (red arrow). Image 2: Endoscopy image demonstrating gastric mass (yellow arrow). Image 3: H&E stain of gastric mass demonstrating smooth muscle cells. Image 4: Positive smooth muscle actin stain.

In vivo recellularization of xenogeneic vascular grafts decellularized with high hydrostatic pressure method in a porcine carotid arterial interpose model.

Autologous vascular grafts are widely used in revascularization surgeries for small caliber targets. However, the availability of autologous conduits might be limited due to prior surgeries or the quality of vessels. Xenogeneic decellularized vascular grafts from animals can potentially be a substitute of autologous vascular grafts. Decellularization with high hydrostatic pressure (HHP) is reported to highly preserve extracellular matrix (ECM), creating feasible conditions for recellularization and vascular remodeling after implantation. In the present study, we conducted xenogeneic implantation of HHP-decellularized bovine vascular grafts from dorsalis pedis arteries to porcine carotid arteries and posteriorly evaluated graft patency, ECM preservation and recellularization. Avoiding damage of the luminal surface of the grafts from drying significantly during the surgical procedure increased the graft patency at 4 weeks after implantation (P = 0.0079). After the technical improvement, all grafts (N = 5) were patent with mild stenosis due to intimal hyperplasia at 4 weeks after implantation. Neither aneurysmal change nor massive thrombosis was observed, even without administration of anticoagulants nor anti-platelet agents. Elastica van Gieson and Sirius-red stainings revealed fair preservation of ECM proteins including elastin and collagen after implantation. The luminal surface of the grafts were thoroughly covered with von Willebrand factor-positive endothelium. Scanning electron microscopy of the luminal surface of implanted grafts exhibited a cobblestone-like endothelial cell layer which is similar to native vascular endothelium. Recellularization of the tunica media with alpha-smooth muscle actin-positive smooth muscle cells was partly observed. Thus, we confirmed that HHP-decellularized grafts are feasible for xenogeneic implantation accompanied by recellularization by recipient cells.

Leiomyosarcoma of Inferior Vena Cava involving the Liver– A rare case report

Sarcomas are very rare tumours and 10-30% are located in retro peritoneum. Out of all the sarcoma cases only 1% cases are of Leiomyosarcoma. We reported a case of 60 year female came with chief complaints of pain abdomen and loss of weight. On palpation there was tenderness in the right hypochondrium and was evaluated. MRI abdomen showed a well-defined heterogenous mass of size 8.8 ×7.9×8.2cm noted in the suprarenal location which was compressing inferiorvenacava (IVC) and also showed displacement of IVC with focal intraluminal extension with possibility of Leiomyosarcoma of IVC or retro peritoneum or hepato renal region. Section from trucut biopsy of Liver showed loss of normal liver architecture by pleomorphic spindle tumour cells arranged in bundles. Cells showing marked nuclear pleomorphism with enlarged irregular nucleus with many mononucleate and multi nucleate gaint cells suggestive of malignant spindle cell neoplasm. Immuno Histochemistry (IHC) staining was showed diffuse positivity for smooth muscle Actin, Desmin. Treatment was initiated with adjuvant chemotherapy. Later IVC reconstruction along with resection of supra renal mass was done. Keywords: Leiomyosarcoma of inferiorvenacava (IVC), Malignant spindle cell neoplasm of Liver.

Cutaneous leiomyosarcoma: a 20-year retrospective study and review of the literature

BackgroundCutaneous leiomyosarcoma is a rare malignant neoplasm with muscular origin, representing 2%-3% of all cutaneous soft tissue sarcomas. ObjectivesThe aim of this study was to characterize clinicopathological features of patients diagnosed with cutaneous leiomyosarcoma in our center over the last 20-years. MethodsA retrospective study of patients with a histopathological diagnosis of leiomyosarcoma between 1999 and 2018 was conducted. ResultsEleven patients were diagnosed with cutaneous leiomyosarcoma during this period. Most cases occurred in men (n = 7). Age at presentation ranged from 47 to 92 years (mean 64.9 years). Head and neck were the most frequently involved locations (n = 5). Ten leiomyosarcoma were dermal, with one cutaneous metastasis. Immunohistochemical staining was available for 7 patients, demonstrating positivity for smooth muscle actin in all of them. All neoplasms were treated surgically. Mean survival was 32.2-months. Study limitationsThis was a retrospective study based on medical and pathological records. ConclusionsHistopathology is essential for the diagnosis of leiomyosarcoma, usually revealing a dermal or subcutaneous lesion composed of intertwined fascicles of smooth muscle fibers. Immunohistochemistry is then used to adequately differentiate leiomyosarcoma from other spindle cell tumors. When dealing with cutaneous leiomyosarcoma, it is advisable to carefully evaluate the depth of subcutaneous extension, since even minimal subcutaneous involvement may be associated with a poorer prognosis.

Leiomyoma of ileum causing intestinal obstruction: A rare presentation

Leiomyoma is a benign mesenchymal neoplasms arising from smooth muscles which accounts for 20%–30% of all benign gastrointestinal tumours. The occurrence of leiomyoma in ileum is rare. Very few cases of intestinal obstruction due to intestinal leiomyoma have been documented till date as per our knowledge. Here, we report a case of leiomyoma of ileum causing intestinal obstruction in a young woman who presented with pain in abdomen since 7 days. Intraoperative findings showed presence of 15 cm × 14 cm × 12 cm mesenteric tumour encircling the ileum. Microscopically, the benign spindled tumour cells were arranged in whorled pattern. Immunohistochemistry showed positivity for smooth muscle actin and negativity for CD117. One should always consider this rare entity in differential diagnosis of patients presenting with intestinal obstruction.

Angioleiomyoma presenting as a nodular swelling of leg: Report of a rare painful benign soft tissue tumor

Angioleiomyoma is a slow-growing benign pericytic tumor originating from the tunica media layer of blood vessel wall and represents 4–5% of all benign soft tissue tumors. Vascular leiomyomas show a greater predilection for the lower extremities than other superficial leiomyomas. Excisional biopsy of the tumor is both diagnostic and curative, with a low recurrence rate reported in the literature and excellent prognosis. Malignant transformation is very rare. Whenever a patient presents with a painful mass in the lower extremity, the diagnosis of leiomyoma should be considered. We present a case of a 30-year-old male with angioleiomyoma of left lower leg who presented with painful slow growing nodular swelling since six years. The mass was excised and on microscopic examination a diagnosis of angioleiomyoma was rendered, which was confirmed by positivity for smooth muscle actin on immunohistochemistry. Keywords: Angioleiomyoma, Angiomyoma, Pericytic tumor, SMA, Vascular leiomyoma.

S3013 The Two Challenges in Management of Gastric Glomus Tumors

INTRODUCTION: Gastric glomus tumors (GGTs) are rare gastrointestinal lesions originating from the neuromuscular arterial canal or vascular lumen which share many overlapping features with other stromal lesions. Even though most cases of GGTs are benign, there is lack of reliable histological features predictive of tumor behavior. CASE DESCRIPTION/METHODS: A 42-year-old male with hypertension and gastroesophageal reflux disease presented with a history of intermittent left upper quadrant pain and non-bloody, non-bilious emesis. He was afebrile and had a soft, non-distended abdomen. Labs were notable only for mild iron deficiency anemia. Contrast-enhanced computed tomography (CT) of the abdomen showed a 3.2 × 2.7 × 3.1 cm soft tissue mass with central calcification and vascularity along the lesser curvature of the stomach. Esophagogastroduodenoscopy (EGD) demonstrated a 3 cm submucosal ulcerated mass at the incisura (Figure 1). Endoscopic ultrasonography (EUS) showed a well-defined hypoechoic lesion arising from the muscularis propria, with maximum diameter of 3.3 cm (Figure 2). Further investigation with fine needle aspiration (FNA) of the lesion demonstrated – small, round and uniform cells intermixed with capillary-sized vessels along with in-tumor-calcification, mild pleomorphism, and sparse Ki67 staining, but no evidence of mitotic activity (Figure 3A) which demonstrated positivity for smooth muscle actin and synaptophysin and weak stained for placental alkaline phosphatase suggestive of a glomus tumor (Figure 3B). The tumor cells lacked markers more indicative of an epithelioid gastrointestinal stromal tumor including: CD117, CD34, Desmin, S-100, and DOG1. After discussing surveillance versus endoscopic/surgical resection options with the patient, surgical wedge resection of the tumor was performed for definitive management. Pathology of excision specimen was consistent with a benign gastric glomus tumor. DISCUSSION: GGTs pose two challenges: 1) differentiation from more common stromal/mesenchymal tumors and 2) prediction of tumor behavior. In our patient, although EUS and FNA showed small benign cells, given the patient’s young age, symptomatic presentation, ulcerated lesion appearance and neovascularity, we proceeded with resection after shared decision making. Given the rarity of GGTs, this case highlights the importance of establishing an accurate diagnosis and the various factors that must be taken into consideration to best determine malignant potential.Figure 1.: A) EGD of pre-pyloric stomach showing multiple, small non-bleeding erosions near the antrum (yellow arrows). B) EGD showing a large, submucosal mass with no bleeding and no stigmata of recent bleeding was found at the incisura (yellow arrows).Figure 2.: EUS showing a hypoechoic mass in the stomach incisura angularis (yellow arrows).Figure 3.: A) Hematoxylin and Eosin (H& E) staining of FNA (30x magnification). B) Smooth muscle actin (SMA) stain on FNA specimen which is characteristically positive in glomus tumors (16x magnification).