Alexandros Mekras

Dr. Alexandros Mekras

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Research Focus & Metrics

Academic Career Length

16Years (2011-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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25 July 2018 in BMC Surgery
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Journal Article
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AMAlexandros Mekras
Alexandros Mekras
VKVeit Krenn
Veit Krenn
APAristotelis Perrakis
Aristotelis Perrakis
RCRoland Croner
Roland Croner
Vasileios KallesVasileios Kalles
Vasileios Kalles
Nikolaos VassosNikolaos Vassos
Nikolaos Vassos
Schwannomas of gastrointestinal tract are rare, mostly benign and notably different neoplasms from conventional schwannomas that arise in soft tissue or the central nervous system. These tumors are of clinical importance since they should always be considered in the differential diagnosis of submucosal lesions of gastrointestinal tract. Seven patients with a pathologically proven gastrointestinal schwannoma were identified in our series of mesenchymal tumors and reviewed retrospectively. Clinicopathological and immunohistochemical parameters along with the follow-up results were analysed. The series included two males and five females, with a mean age 69 years (range, 39–81). Most patients were asymptomatic on presentation, except for two patients with abdominal pain. In the other cases (n = 5), the tumor was an incidental finding during other medical, imaging or surgical procedures. The tumors were located in the stomach (n = 4) and in the small intestine (n = 3) with an average size of 29 mm (range, 12–70). A preoperative diagnosis was achieved only in one case with a CT-guided core biopsy. Otherwise the clinical, intraoperative, endoscopic or radiological findings were unspecific. Patients with gastric tumor underwent either laparoscopic (n = 2) or open (n = 2) gastric wedge resection of the tumor; in the cases of intestinal tumor (n = 3) a segmentectomy was performed. Pathological examination revealed solid homogenous tumors, which were highly cellular and composed of spindle cells with positive staining for S100 protein, and confirmed the diagnosis of schwannoma. All tumors were negative for c-Kit, smooth muscle actin, desmin and DOG-1 and showed very low proliferation index. There were negative resection margins and no malignant variants were recognized. At an average follow-up of 60 months (range, 24–185) all patients were free of disease with no signs of recurrence or metastases and acceptable gastrointestinal function. Schwannomas are rare, slow-growing and mostly asymptomatic gastrointestinal mesenchymal tumors. They are difficult to be diagnosed preoperatively as endoscopic and radiological findings are nonspecific but histological and immunohistochemical features are of paramount importance to differentiate between benign and malignant schwannomas, or other spindle cell sarcomas. The treatment of choice is complete surgical excision without a conclusive preoperative diagnosis, and the long-term outcome is excellent as these lesions are mostly benign.

10 September 2025 in Journal of Clinical Medicine
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Daniel ParamythiotisDaniel Paramythiotis
Daniel Paramythiotis
DTDimitrios Tsavdaris
Dimitrios Tsavdaris
GTGeorgios Tsavdaris
Georgios Tsavdaris
AHAdam Hatzidakis
Adam Hatzidakis
KPKyriakos Psarras
Kyriakos Psarras
AMAntonios Michalopoulos
Antonios Michalopoulos
Liver malignancies are among the most prevalent cancers worldwide and can be managed using various therapeutic approaches. However, the available options for treating these malignancies are characterized by several limitations. Histotripsy, which was recently approved by the Food and Drug Administration (FDA), seems to be promising for overcoming these limitations. It is an emerging non-invasive, non-thermal ultrasound technology, which is based on the controllable initiation of cavitation from endogenous nanometer-scale gas pockets within tissues. Numerous preclinical studies as well as three clinical studies highlight this technique as feasible, safe, and effective. Among its advantages are the lack of thermal injury, its non-invasive nature, its immunopreserving and possibly immunostimulating ability, as well as the low number of complications that accompany it. Nonetheless, long-term clinical outcomes are still lacking, and further studies are needed to establish its definitive role in liver cancer treatment. In conclusion, histotripsy shows strong potential to become a transformative tool in liver oncology, but continued clinical evaluation is essential to validate its long-term efficacy and integration into standard care.

2 September 2011 in Techniques in Coloproctology
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Journal Article
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AMAlexandros Mekras
Alexandros Mekras
AMA. Michalopoulos
A. Michalopoulos
VPV. N. Papadopoulos
V. N. Papadopoulos
DMD. Mekras
D. Mekras
VKV. Kalles
V. Kalles
GBG. Basdanis
G. Basdanis

2 September 2011 in Techniques in Coloproctology
Verified
Journal Article
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GBG. Basdanis
G. Basdanis
AMAlexandros Mekras
Alexandros Mekras
VPV. N. Papadopoulos
V. N. Papadopoulos
EKE. Karamanlis
E. Karamanlis
DPD. Paramythiotis
D. Paramythiotis
AMA. Michalopoulos
A. Michalopoulos

25 December 2025 in Cancers
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AMAlexandros Mekras
Alexandros Mekras
DTDimitrios Tsavdaris
Dimitrios Tsavdaris
DMDimosthenis Mekras
Dimosthenis Mekras
AVAlexandra Vasilakou
Alexandra Vasilakou
Daniel ParamythiotisDaniel Paramythiotis
Daniel Paramythiotis
MBMattheos Bobos
Mattheos Bobos
Background/Objectives: Colorectal cancer (CRC) is the third most commonly occurring cancer. Apoptosis is a fundamental cellular process of programmed cell death, and although many pathways for inducing apoptosis may exist, only the intrinsic and the extrinsic pathways have been demonstrated in detail. This study investigated the expression of BAD, BID, BCL2, MDM2, p53, Ki-67, and PUMA in primary CRC, paired lymph node metastases, and adjacent normal mucosa and explored their associations with clinicopathologic features and patient outcomes. Methods: One hundred thirty patients who underwent surgery for resectable CRC were included in the study. FFPE tumor tissue samples were prospectively collected and used for the construction of the TMA blocks from the primary tumor, paired lymph node metastasis, and paired normal mucosa. Immunohistochemistry for BAD, BID, BCL2, MDM2, p53, Ki-67, and PUMA antibodies was performed. Results: Univariate analysis showed reduced cancer-specific (CSS), disease-free (DFS), and overall survival (OS) in patients with lymphatic invasion, ≥4 positive lymph nodes, poorly differentiated tumors, older age (≥65), right-sided tumors, stage IIIC disease, or no chemotherapy. Multivariate analysis identified lymphovascular invasion, ≥4 metastatic nodes, and high Ki-67 as independent predictors of worse DFS and CSS, with low BAD expression additionally predicting DFS. For OS, adverse predictors included nodal burden, tumor location, absence of chemotherapy, and high p53, MDM2, and Ki-67 expression. Notably, combined high PUMA and low p53 expression independently predicted poorer CSS and OS. Conclusions: High expression of PUMA combined with low expression of p53 and a high expression of Ki-67 were independent unfavorable prognostic indicators for both OS and CSS. Further studies are required to clarify the prognostic and therapeutic role of these markers in CRC.

30 June 2025 in Diseases
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Daniel ParamythiotisDaniel Paramythiotis
Daniel Paramythiotis
ASAntonia Syrnioti
Antonia Syrnioti
DTDimitrios Tsavdaris
Dimitrios Tsavdaris
ASAikaterini Smprini
Aikaterini Smprini
AMAlexandros Mekras
Alexandros Mekras
ACAngeliki Cheva
Angeliki Cheva
Endometriosis is a clinical entity affecting up to 10% of women of reproductive age, characterized by ectopic endometrial tissue outside the uterine cavity. While extrapelvic endometriosis has been documented, pancreatic endometriosis remains extremely rare and poses significant diagnostic challenges due to its similarity to other pancreatic diseases. At the same time, splenic mesothelial cysts are also rare and typically benign. This report presents a unique case of pancreatic endometriosis coexisting with a splenic mesothelial cyst in a 31-year-old woman. The patient presented to the emergency department with complaints of persistent epigastric and low back pain. She noted having similar symptoms approximately a year prior. Her past medical history was otherwise unremarkable, and there was no known family history of pancreatic disease or neoplasms. Initial imaging revealed a 3.8 cm cystic lesion in the pancreatic tail, with features suggestive of mucinous cystadenoma. Following clinical evaluation and confirmation of the cyst’s nature through endoscopic ultrasound-guided biopsy, the patient subsequently underwent laparoscopic distal pancreatectomy and splenectomy due to worsening symptoms. Gross examination revealed a multilocular pancreatic cyst with a smooth, hemorrhagic wall. Microscopic analysis showed the cyst to be lined by cuboidal to columnar epithelium, consistent with pancreatic endometriosis, confirmed by immunohistochemical staining. The spleen showed cystic formations, diagnosed as a multifaceted mesothelial cyst. In conclusion, this report is the first to document the coexistence of pancreatic endometriosis and splenic mesothelial cysts, highlighting the importance of accurate imaging and pathologic evaluation in the diagnosis of these rare conditions. Early diagnosis and surgical intervention lead to favorable outcomes, reinforcing the importance of comprehensive diagnostic strategies.