Comparison between two types of needles for Endoscopic Ultrasound (EUS)-guided fine aspiration biopsy of pancreatic and upper gastrointestinal masses.

BACKGROUND: EUS-guided fine-needle aspiration (FNA) has long been the main method for sampling pancreatic lesions. Recently, the method of fine-needle biopsy (FNB) was introduced in practice, allowing for the acquisition of tissue cores while aspirating the lesion. We hereby report our experience with a new FNB needle compared with the standard FNA needle. METHODS: Retrospective data from our department were collected on patients who underwent FNB using the Acquire EUS-FNB needle (Boston Scientific, Massachusetts) and FNA using the EchoTip Ultra EUS-FNA Needle (Cook Medical, Indiana) between January 2017 and February 2018. The cases were reviewed independently by two cytopathologists and evaluated for the presence of cell block or core tissue material, adequacy for potential ancillary testing, and number of passes. RESULTS: The number of passes ranged from 1 to 16, with a mean of 5.52 ± 3.74 in the FNA group, and from 1 to 6, with a mean of 2.74 ± 1.11 passes in the FNB group (P < .0001). Tissue cores were present in 87.23% of the FNB needle samples. A cell block was adequate in 36.36% of cases using the FNA needle. The diagnostic yield as well as the adequacy for ancillary testing were significantly different between the two groups (P = .0001). The tumor size, location and patients' demographics were not statistically significant between the two groups. CONCLUSION: Compared with the conventional needle, the new FNB needle was associated with a lower number of passes and a better yield for histological material.

Enhancement of the gut barrier integrity by a microbial metabolite through the Nrf2 pathway.

The importance of gut microbiota in human health and pathophysiology is undisputable. Despite the abundance of metagenomics data, the functional dynamics of gut microbiota in human health and disease remain elusive. Urolithin A (UroA), a major microbial metabolite derived from polyphenolics of berries and pomegranate fruits displays anti-inflammatory, anti-oxidative, and anti-ageing activities. Here, we show that UroA and its potent synthetic analogue (UAS03) significantly enhance gut barrier function and inhibit unwarranted inflammation. We demonstrate that UroA and UAS03 exert their barrier functions through activation of aryl hydrocarbon receptor (AhR)- nuclear factor erythroid 2-related factor 2 (Nrf2)-dependent pathways to upregulate epithelial tight junction proteins. Importantly, treatment with these compounds attenuated colitis in pre-clinical models by remedying barrier dysfunction in addition to anti-inflammatory activities. Cumulatively, the results highlight how microbial metabolites provide two-pronged beneficial activities at gut epithelium by enhancing barrier functions and reducing inflammation to protect from colonic diseases.

miR-301a expression: Diagnostic and prognostic marker for prostate cancer.

BACKGROUND: Prostate-specific antigen screening for prostate cancer (CaP) remains controversial. This study establishes the role of microRNA 301a (miR-301a) as a supplemental biomarker that can distinguish between patients with benign prostate hyperplasia and clinically significant CaP. We evaluate the ability of miR-301a to predict the adverse pathology of CaP. METHODS: In the first cohort, serum and prostate tumor samples were obtained from thirteen patients with Benign prostate hyperplasia (BPH), twelve patients with Gleason 6, and sixteen patients with Gleason 7 prostate adenocarcinoma. In the second cohort, 40 prostatectomy cases were selected (BPH:12, Gleason 6:12 and Gleason 7:16). MiRNA was extracted from serum and tumor samples. Quantitative reverse transcription-polymerase chain reaction was performed for detection of miR-301a. To understand the molecular role of miR-301a, we performed cell viability, Western blots, promoter analysis, overexpression, and silencing studies in BPH and DU-145 cell lines. RESULTS: MiR-301a demonstrated a significantly higher expression in both serum and tumor tissue in patients with CaP when compared to patients with BPH (P = 0.011 and 0.013 for serum and tissue expression, respectively). Expression of miR-301a in prostatectomy specimens correlated with increased Gleason score. We demonstrated that miR-301a inhibited the pro-apoptotic function of RUNX3, and activated ROCK1-mediated pro-survival signal in CaP. Silencing miR-301a initiated the pro-apoptotic function of RUNX3 by inhibiting ROCK1 expression in CaP cells. CONCLUSIONS: Expression of miR-301a could be a valuable adjunct tool for stratifying patients with elevated prostate-specific antigen, as well as those diagnosed with CaP. Including the miR-301a as an additional variable in MSKCC post-prostatectomy nomogram improved its ability in facilitating clinical decision-making.

The chemopreventive effect of withaferin A on spontaneous and inflammation-associated colon carcinogenesis models.

Chemopreventive effects and associated mechanisms of withaferin A (WA) against intestinal and colon carcinogenesis remain unknown. We investigated the chemopreventive effect of WA on transgenic adenomatous polyposis coli (APCMin/+) mouse and chemically induced azoxymethane/dextran sodium sulfate (AOM/DSS) models of intestinal and colon carcinogenesis. Oral WA administration (4 and 3 mg/kg) inhibited tumor initiation and progression of intestinal polyps formation in APCMin/+ mice and colon carcinogenesis in the AOM/DSS mouse model. WA-administered mice showed a significant reduction in both number [duodenum, 33% (P > 0.05); jejunum, 32% (P < 0.025); ileum, 43% ( P < 0.001); and colon 59% (P < 0.01] and size of polyps in APCMin/+ mice compared with the respective controls. Similarly, tumor multiplicity was significantly reduced (P < 0.05) in the colon of WA-administered AOM/DSS mice. Pathological analysis showed reduced adenomas and tissue inflammation in WA-administered mouse models. Molecular studies suggested that WA inhibited the expression of inflammatory (interluekin-6, tumor necrosis factor-alpha and cyclooxygenase-2), pro-survival (pAKT, Notch1 and NF-κB) markers in APCMin/+ and AOM/DSS models. The results suggest that WA is a potent agent for preventing colon carcinogenesis and further investigation is required to show clinical utility of the agent.

Sarcomatous Component in Uterine Carcinosarcomas Correlates With Advanced Stage and Poorer Prognosis.

Uterine carcinosarcomas, also known as malignant-mixed mullerian tumors, are rare and highly aggressive tumors whose prognostic factors remain controversial. The stage at the time of presentation is the most important prognostic factor thus far, but little information exists on the prognostic impact of the sarcomatous component (SC) in these tumors. We reviewed 21 cases of uterine carcinosarcomas and estimated the volume of the SC in each case. This information was correlated with the stage of the tumor at presentation. The percentage of the SC was also used to stratify the patients into 2 cohorts (high percentage of SC and low percentage of SC), and the 2 patient cohorts were compared based on the available follow-up data to identify prognostic differences. Patients with a lower concentration of SC (<30%) typically presented with low stage of disease when compared with their counterparts. Although not statistically significant (P=0.1966), our data suggest a correlation between a lower concentration of SC with longer follow-up and longer survival rates when compared with those of patients presenting with higher volumes of the SC (≥30%). Greater volume of the SC is seen in advanced stage tumors, which could serve as an indicator of prognosis.

Sellar and Suprasellar Anaplastic Hemangiopericytoma in a 34-Year Old Man.

Central nervous system hemangiopericytomas are rare, representing <1% of all primary central nervous system tumors. Hemangiopericytomas of the sellar region are exceptionally rare. Here we present a case of a sellar/suprasellar anaplastic hemangiopericytoma.The patient is a 34 year old man with a history of a resected pituitary tumor, diagnosed as a pituitary adenoma per the patient, who presented with bitemporal hemianopsia. Radiology revealed a 3.7 cm enhancing sellar/suprasellar mass with local mass effect, consistent with a pituitary adenoma. On resection, the mass was diagnosed as anaplastic hemangiopericytoma, WHO grade III. The patient experienced residual tumor with two further resections before expiring of a pulmonary embolus seven months later.There are only 10 previously documented cases of sellar/suprasellar hemangiopericytoma in the English-speaking world literature. This is the third case of anaplastic hemangiopericytoma in this region. These cases should be recorded until meaningful conclusions about therapy and prognosis can be established.

Inhibition of autophagy prevents cadmium-induced prostate carcinogenesis.

BACKGROUND: Cadmium, an established carcinogen, is a risk factor for prostate cancer. Induction of autophagy is a prerequisite for cadmium-induced transformation and metastasis. The ability of Psoralidin (Pso), a non-toxic, orally bioavailable compound to inhibit cadmium-induced autophagy to prevent prostate cancer was investigated. METHODS: Psoralidin was studied using cadmium-transformed prostate epithelial cells (CTPE), which exhibit high proliferative, invasive and colony forming abilities. Gene and protein expression were evaluated by qPCR, western blot, immunohistochemistry and immunofluorescence. Xenograft models were used to study the chemopreventive effects in vivo. RESULTS: Cadmium-transformed prostate epithelial cells were treated with Pso resulting in growth inhibition, without causing toxicity to normal prostate epithelial cells (RWPE-1). Psoralidin-treatment of CTPE cells inhibited the expression of Placenta Specific 8, a lysosomal protein essential for autophagosome and autolysosome fusion, which resulted in growth inhibition. Additionally, Pso treatment caused decreased expression of pro-survival signalling proteins, NFκB and Bcl2, and increased expression of apoptotic genes. In vivo, Pso effectively suppressed CTPE xenografts growth, without any observable toxicity. Tumours from Pso-treated animals showed decreased autophagic morphology, mesenchymal markers expression and increased epithelial protein expression. CONCLUSIONS: These results confirm that inhibition of autophagy by Pso plays an important role in the chemoprevention of cadmium-induced prostate carcinogenesis.

Targeting aberrant expression of Notch-1 in ALDH+ cancer stem cells in breast cancer.

We have previously reported that high aldehyde dehydrogenase (ALDH) enzyme activity in breast cancer cells results in breast cancer stem cell (BCSC) properties by upregualting Notch-1 and epithelial mesenchymal markers. This results in chemoresistance in breast cancer. Here, we examined the functional and clinical significance of ALDH expression by measuring the ALDH levels in breast cancer tissues by immunohistochemistry. There was a significantly higher ALDH expression in higher grade breast cancer tumor tissues (Grade- II and III) versus normal breast tissues. Injection of BCSC (ALDH+ and CD44+ /CD22- ) cells resulted in aggressive tumor growth in athymic mice versus ALDH- cells. The ALDH+ and CD44+ /CD22- tumors grow rapidly and are larger than ALDH- tumors which were slow growing and smaller. Molecularly, ALDH+ tumors expressed higher expression of Notch-1 and EMT markers than ALDH- tumors. Oral administration of the naturally occurring Psoralidin (Pso, 25 mg/kg of body weight) significantly inhibited the growth in ALDH+ and ALDH- tumors as well. Psoralidin inhibited Notch-1 mediated EMT activation in ALDH+ and ALDH- tumors-this confirms our in vitro findings. Our results suggest that Notch-1 could be an attractive target and inhibition of Notch-1 by Psoralidin may prevent pathogenesis of breast cancer as well as metastasis. © 2016 Wiley Periodicals, Inc.

Strong NFκB Expression is Associated With High-grade Dysplasia in Barrett's Esophagus.

Nuclear factor kappa B (NFκB) is a transcription factor that regulates the activation of genes involved in proinflammatory response and growth. In this study, we utilized immunohistochemical stains for 2 of the NFκB molecules (RELA and NFκB-1) to evaluate the expression of NFκB in Barrett's esophagus (BE). Forty-three cases of BE [17 cases with no dysplasia, 16 cases with low-grade dysplasia (LGD), and 10 cases with high-grade dysplasia (HGD)], 10 normal esophageal biopsies, and 9 cases of esophageal adenocarcinoma were evaluated. Expression of NFκB-1 and RELA did not occur in normal esophageal squamous mucosa. BE without dysplasia showed weak expression of RELA and NFκB-1 in 35% and 65% of cases, respectively. BE with LGD showed weak expression of RELA and NFκB-1 in 50% and 75% of cases, respectively. Strong expression of RELA and NFκB-1 did not occur in BE without dysplasia or with LGD. BE with HGD showed strong expression of RELA and NFκB-1 in 80% and 90% of cases, respectively. All cases of adenocarcinoma showed strong expression of both RELA and NFκB-1. There was a progressive increase in staining intensity of RELA and NFκB-1 along the metaplasia-dysplasia-adenocarcinoma pathway. Strong expression of NFκB is associated with HGD and adenocarcinoma (P<0.0001). We showed that strong expression of NFκB-1 and RELA correlates highly with BE with HGD and adenocarcinoma.

Nephroblastoma Arising from Primary Testicular Germ Cell Tumor: A Case Report and Literature Review.

Adult extrarenal nephroblastoma is a very rare tumor. Nephroblastoma arising from primary testicular germ cell tumor is exceedingly rare. To our knowledge, only three cases have been reported in the English literature. We report a case of a 19-year-old man who presented with a large right testicle. Image studies showed a large retroperitoneal mass along with liver and lung metastases. Orchiectomy demonstrated a mixed germ cell tumor composed of yolk sac tumor, embryonal carcinoma, and mature and immature teratoma with a significant portion of nephroblastoma. The patient received chemotherapy and no recurrence was noted during six months of followup. WT-1 expression was also studied due to the lack of consistency of its expression in testicular nephroblastoma in the literature. We also present a discussion and review of the literature due to its rarity, which indicate an adverse prognosis for patients with nephroblastoma components receiving standard chemotherapeutical regimes for testicular germ cell tumors.

Oral administration of withaferin A inhibits carcinogenesis of prostate in TRAMP model.

We previously reported that withaferin A (WA), a natural compound, deters prostate cancer by inhibiting AKT while inducing apoptosis. In the current study, we examined its chemopreventive efficacy against carcinogenesis in the prostate using the transgenic adenocarcinoma of mouse prostate (TRAMP) model. Two distinct sets of experiments were conducted. To determine whether WA delays tumor progression, it was given before cancer onset, at week 6, and until week 44. To determine its effect after the onset of prostate cancer, it was given from weeks 12 to 35. In both strategies, oral administration of WA effectively suppressed tumor burden when compared to vehicle-treated animals. No toxicity was seen in treated animals at gross pathological examination. Western blot analysis and immunohistochemistry of tumor sections revealed that in TRAMP controls, AKT and pAKT were highly expressed while nuclear FOXO3a and Par-4 were downregulated. On the contrary, treated mice showed inhibition of AKT signaling and activation of FOX03a-Par-4-induced cell death. They also displayed inhibition of mesenchymal markers such as ß-catenin, vimentin, and snail as well as upregulation of E-cadherin. Because expressions of the angiogenic markers factor VIII and retic were downregulated, an anti-angiogenic role of WA is suggested. Overall, our results suggest that WA could be a promising anti-cancer agent that effectively inhibits carcinogenesis of the prostate.

miR-301a expression: A prognostic marker for prostate cancer.

PURPOSE: The diagnosis and treatment of prostate cancer (CaP) continues to be challenging, as prostate-specific antigen (PSA) appears to be overly sensitive and biopsy is the only reliable method for confirmation. Hence, the goal of the study is to identify a biomarker that could distinguish malignant cancer from benign prostatic hyperplasia (BPH) during the early diagnosis of the disease. MATERIALS AND METHODS: A total of 75 formalin fixed paraffin embedded (FFPE) with matching controls, 4 paired metastatic tumors, 6 fresh tumor tissues and BPH (13 cases) with their clinical diagnosis were selected for this study. Prostate cancer cell lines and normal prostate epithelial cell lines were obtained from ATCC and subjected to phenotypic analysis. RESULTS: We observed significant differential expression of miR-301a in CaP samples in comparison to BPH and adjacent benign samples. The overexpression of miR-301a activates the invasion/migration of CaP cells. In contrast, silencing miR-301a expression inhibited the colony-forming ability, adhesion, invasion and migration of CaP cells. Similarly, the overexpression of miR-301a increased cell motility in normal RWPE-1 prostate epithelial cells. Our results suggest that miR-301a is differentially expressed between BPH and CaP specimens and that the expression of miR-301a correlates with biochemical recurrence and/or metastasis in CaP patients. CONCLUSIONS: The expression of miR-301a could be a potential marker for metastasis in CaP patients. Detecting miR-301a expression during diagnosis will avoid wait and watch timelines, thus preventing morbidity.

Cytomorphologic findings and differential diagnosis of pulmonary papillary adenoma: A case report and literature review.

Pulmonary papillary adenoma is a rare tumor of the lung. Some authors refer to it as papillary adenoma of type II pneumocytes. It demonstrates benign behavior, although some references suggest that this tumor may rarely exhibit invasive characteristics. We report a case of pulmonary papilloma adenoma of the lung diagnosed by fine-needle aspiration biopsy and transbronchial biopsy. The patient is a 78-year-old woman, who presented to an outside facility with complaint of confusion after a missed episode of dialysis. On further workup, she was found to have a 3.8 cm irregular mass in the upper lobe of her right lung as visualized on chest CT. Fine-needle aspiration and a concurrent forceps-assisted transbronchial biopsy of the mass were performed. On microscopical examination, tumor cells formed small cohesive papillary fronds. On cytological evaluation, tumor cells were uniform medium-sized epithelial cells with moderate cytoplasm, fine chromatin, and inconspicuous nucleoli. The biopsies showed papillary arrangement of epithelial cells in a background of mild fibrosis and chronic inflammation. There was no piling up of cells and the nuclei were uniform with bland appearance. No mitoses were appreciated, and Ki-67 activity was low. The clinical decision was for observation. The patient suffered no complications after the procedures during 26 months of follow-up. We hereby present this case with a review of the literature. Diagn. Cytopathol. 2016;44:543-547. © 2016 Wiley Periodicals, Inc.

Activation of AKT negatively regulates the pro-apoptotic function of death-associated protein kinase 3 (DAPK3) in prostate cancer.

The activation of AKT governs many signaling pathways and promotes cell growth and inhibits apoptosis in human malignancies including prostate cancer (CaP). Here, we investigated the molecular association between AKT activation and the function of death-associated protein kinase 3 (DAPK3) in CaP. An inverse correlation of pAKT and DAPK3 expression was seen in a panel of CaP cell lines. Inhibition of AKT by wortmannin/LY294002 or overexpression of DAPK3 reverts the proliferative function of AKT in CaP cells. On the other hand, ectopic expression of AKT inhibited DAPK3 function and induced proliferation of CaP cells. In addition, AKT over-expressed tumors exhibit aggressive growth when compared to control vector in xenograft models. The immunohistochemistry results revealed a down-regulation of DAPK3 expression in AKT over-expressed tumors as compared to control tumors. Finally, we examined the expression pattern of AKT and DAPK3 in human CaP specimens - the expected gradual increase and nuclear localization of pAKT was seen in higher Gleason score samples versus benign hyperplasia (BPH). On the contrary, reduced expression of DAPK3 was seen in higher Gleason stages versus BPH. This suggests that inhibition of DAPK3 may be a contributing factor to the carcinogenesis of the prostate. Understanding the mechanism by which AKT negatively regulates DAPK3 function may suggest whether DAPK3 can be a therapeutic target for CaP.

Withaferin-A suppress AKT induced tumor growth in colorectal cancer cells.

The oncogenic activation of AKT gene has emerged as a key determinant of the aggressiveness of colorectal cancer (CRC); hence, research has focused on targeting AKT signaling for the treatment of advanced stages of CRC. In this study, we explored the anti-tumorigenic effects of withaferin A (WA) on CRC cells overexpressing AKT in preclinical (in vitro and in vivo) models. Our results indicated that WA, a natural compound, resulted in significant inhibition of AKT activity and led to the inhibition of cell proliferation, migration and invasion by downregulating the epithelial to mesenchymal transition (EMT) markers in CRC cells overexpressing AKT. The oral administration of WA significantly suppressed AKT-induced aggressive tumor growth in a xenograft model. Molecular analysis revealed that the decreased expression of AKT and its downstream pro-survival signaling molecules may be responsible for tumor inhibition. Further, significant inhibition of some important EMT markers, i.e., Snail, Slug, ß-catenin and vimentin, was observed in WA-treated human CRC cells overexpressing AKT. Significant inhibition of micro-vessel formation and the length of vessels were evident in WA-treated tumors, which correlated with a low expression of the angiogenic marker RETIC. In conclusion, the present study emphasizes the crucial role of AKT activation in inducing cell proliferation, angiogenesis and EMT in CRC cells and suggests that WA may overcome AKT-induced cell proliferation and tumor growth in CRC.

Impact of immediate evaluation of touch imprint cytology from computed tomography guided core needle biopsies of mass lesions: Single institution experience.

BACKGROUND: Computed tomography (CT) guided core needle biopsy (CT-guided CNB) is a minimally invasive, safe and effective manner of tissue sampling in many organs. The aim of our study is to determine the impact of on-site evaluation of touch imprint cytology (TIC) to minimize the number of passes required to obtain adequate tissue for diagnosis. DESIGN: A retrospective review of all CT-guided CNBs performed during 4 year period, where pathologists were present for on-site TIC evaluation. Each case was evaluated for the number of passes required before TIC was interpreted as adequate for diagnosis. RESULTS: A total of 140 CT-guided CNBs were included in the study (liver, lung, kidney, sacral, paraspinal, omental, splenic and adrenal masses). Of the 140 cases, 109 were diagnosed as malignant, 28 as benign and three insufficient. In 106 cases (75.7%), the biopsies were determined adequate by TIC on the first pass, 19 cases (13%) on the second pass and 7 cases (5%) on the third pass. Only in 5 cases (3.6%), more than three passes were required before diagnostic material was obtained. Three cases (2.14%) were interpreted as inadequate both on TIC and on the final diagnosis. Of the biopsies deemed adequate on the first pass, 71% resulted in either termination of the procedure, or only one additional pass was obtained. In five cases, based on the TIC evaluation, a portion of the sample was sent for either flow cytometric analysis or cytogenetic studies. CONCLUSIONS: In the majority of cases, adequate material was obtained in the first pass of CT-guided CNB and once this was obtained, either no additional passes, or one additional pass was performed. This study demonstrates the utility of on-site evaluation in minimizing the number of passes required for obtaining adequate diagnostic material and for proper specimen triage for ancillary studies, which in turn decreases the risk to the patient and costs. However, tumor exhaustion in the tissue as a result of TIC is an important pitfall of the procedure, which occurred in 9 (8.2%) of our malignant cases.

Ependymoma and carcinoid tumor associated with ovarian mature cystic teratoma in a patient with multiple endocrine neoplasia I.

Ovarian teratomas rarely undergo new neoplastic transformation and account for a small percentage of malignant ovarian germ cell neoplasms. Here we report a case of a 51-year-old woman with multiple endocrine neoplasia type I (MEN I) who was found to have an ependymoma and neuroendocrine tumor (trabecular carcinoid) associated with mature cystic teratoma of her left ovary. The ependymoma component displayed cells with round nuclei and occasional small nucleoli which were focally arranged in perivascular pseudorosettes and true rosettes. Rare mitoses were identified. No necrosis was present. Immunohistochemical staining was positive for S-100 and GFAP. The Ki67 proliferation index was very low (2-3%). In contrast, the endocrine tumor component was composed of small uniform cells with eosinophilic cytoplasm, round nuclei, and speckled chromatin. Immunohistochemical staining was positive for synaptophysin and focally positive for chromogranin. This rare case illustrates that MEN I may have an influence on the pathogenesis of ovarian teratomas as they undergo malignant transformation.

Parainfluenza virus-3-induced cytopathic effects on lung tissue and bronchoalveolar lavage fluid in a bone marrow transplant recipient: a case report.

Parainfluenza virus type 3(PIV-3) commonly causes respiratory tract infections in hematopoietic stem cell transplant (HSCT) patients. The majority of PIV-3 infections develop in patients who have undergone stem cell transplantation from unrelated donors. From these patients, bronchoalveolar lavage (BAL) fluid and/or lung biopsies are often collected and sent for evaluation of infectious processes. However, cytologic findings associated with a PIV-3 infection in BAL fluid have not been reported in the literature. We describe BAL cytology and lung biopsy findings in a patient who received an HSCT from a related donor and subsequently developed a PIV-3 infection. This patient was noted to have scattered reticular-nodular opacities in both lungs on computed tomogram scan and underwent transbronchial biopsy and BAL of the left lower lobe. Examination of the BAL fluid revealed scattered multinucleated giant cells intermixed with inflammatory cells. The lung biopsy showed organizing pneumonia associated with several multinucleated respiratory epithelial cells containing rare intracytoplasmic inclusions. Gram, periodic acid Schiff, Gomori methenamine silver, and acid fast stains on the biopsy specimen failed to reveal microorganisms. A sample of the BAL fluid sent for respiratory viral culture grew PIV-3. These findings suggest that the presence of giant cells in transplant patients with organizing pneumonia should raise suspicion of a PIV-3 infection.

Low-grade central osteosarcoma of the rib: a case report and brief review of the literature.

Low-grade central osteosarcoma is a rare variant of osteosarcoma which comprises less than 1-2% of all osteosarcomas. Most low-grade osteosarcomas involve long bones, most commonly distal femur, and proximal tibia. Histologically this tumor is difficult to diagnose, and an unusual location makes this diagnosis even more challenging. Here we report a case of low-grade osteosarcoma presenting as a chest wall mass involving the left 6th-8th ribs. This unusual site of presentation significantly added to the diagnostic difficulties of this rare tumor with challenging histologic features. To the best of our knowledge, only six cases of low-grade central osteosarcoma of the ribs have been reported in the English literature.

Tumor-associated primo vascular system is derived from xenograft, not host.

The primo vascular system (PVS), which is composed of very small primo-vessels (PV) and primo-nodes (PN), has recently emerged as a third component of circulatory system. Here, we report the presence of a tumor derived PVS in murine xenografts of human histiocytic lymphoma (U937) in close proximity to the tumor. Within this system, PNs are small (~500-600 µM diameter) membranous sac-like structures which contain numerous small cells which can be demonstrated by DAPI staining. Hematoxylin and Eosin (H&E) staining of the peri-tumoral PVS shows the presence of loose structures lined by fibroblasts but filled with dense fibers, cells, lacunae and nerve-like structures. The origin and type of cells within the PVS was characterized by immunostaining with antibodies for CD68, CD45 and lysozyme. The results of these studies reveal that the PVS of the xenograft originates from the human U937 tumor cells. qRT-PCR analysis of mRNA isolated from PVS cells reveals a striking predominance of human, rather than mouse, sequences. Of particular interest, human stem cell specific transcription factors were overexpressed, most notably KLF4, an upstream regulator of NANOG which maintains the pluripotent and undifferentiated state of stem cells. These results suggest that the cells present within the PVS are derived from the human xenograft and suggests that the primo-vessels associated with the xenografted tumor may provide a safe haven for a select population of cancer stem cells. Further understanding of the biological properties of these cells may allow the development of new anti-cancer interventions.