Clinicopathological and prognostic significance of DNA mismatch-repair protein expression in gastric adenocarcinoma

Although the significance of DNA mismatch repair (MMR) protein expression in colorectal cancer is well-established, it remains contentious in extra-colorectal cancers and mainly in gastric adenocarcinoma. Data from Africa and Arab world remain limited. This study explored the MMR expression in gastric adenocarcinoma and evaluated its clinicopathological and prognostic signification among Tunisian patients. A retrospective study of 72 gastric adenocarcinomas was carried out. Clinicopathological particularities and patient outcomes were recorded. MMR expression was determined by immunohistochemistry on whole sections of archived material. Survival analysis was realized utilizing the Kaplan-Meier estimates and Log-Rank test. Expression of MMR proteins was observed in 84.7% of gastric adenocarcinoma samples. The 11 remaining samples (15.3%) exhibited an altered pattern of MMR protein. A significant association was identified between deficient MMR expression and advanced age (p = 0.03), intestinal type (p = 0.04) and lymph node metastases (p = 0.04). No other significant relationship was observed with the remaining selected tumor features. Patient survival was significantly associated with lymph node invasion (p = 0.002), distant metastases (p = 0.02) and tumor differentiation (p = 0.03), but not with MMR status (p = 0.83). MMR deficiency was related to advanced-age, intestinal type and nodal metastasis, but not to survival of Tunisian patients with gastric adenocarcinoma. Larger multicenter studies with additional molecular investigation are required to more explore these tumors.

Bien que l'importance de l'expression des protéines de réparation des mésappariements de l'ADN (MMR) dans le cancer colorectal soit bien établie, elle reste controversée dans les cancers extra-colorectaux et principalement dans l'adénocarcinome gastrique. Les données de l'Afrique et du monde arabe restent limitées. Cette étude a exploré l'expression des protéines MMR dans l'adénocarcinome gastrique et a évalué sa signification clinicopathologique et pronostique chez les patients tunisiens. Une étude rétrospective de 72 adénocarcinomes gastriques a été réalisée. Les particularités clinicopathologiques et pronostiques des patients ont été enregistrées. L'expression des protéines MMR a été déterminée par immunohistochimie. L'analyse de survie a été réalisée en utilisant la méthode de Kaplan-Meier et le test Log-Rank. L'expression des protéines MMR a été observée dans 84,7 % des échantillons d'adénocarcinome gastrique. Les 11 cas restants (15,3 %) présentaient un profil d'expression altérée des protéines MMR. Une association significative a été identifiée entre l'expression déficiente de MMR et l'âge avancé (p = 0,03), le type intestinal (p = 0,04) et les métastases ganglionnaires (p = 0,04). Aucune autre relation significative n'a été observée avec les autres caractéristiques tumorales sélectionnées. La survie des patients était significativement associée à l'envahissement des ganglions lymphatiques (Log Rank, p = 0,002), aux métastases à distance (Log Rank, p = 0,02) et à la différenciation tumorale (Log Rank, p = 0,03), mais pas à l'expression de MMR (Log Rank, p = 0,03). Rang, p = 0,83). Le déficit de l'expression des protéines MMR était lié à l'âge avancé, au type intestinal et aux métastases ganglionnaires, mais pas à la survie des patients tunisiens ayant un adénocarcinome gastrique. Des études multicentriques avec des investigations moléculaires supplémentaires sont nécessaires pour explorer davantage le cancer gastrique avec expression déficiente des protéines MMR.

Signification of forkhead box A1 (FOXA1) expression in thyroid cancers.

BACKGROUND: Forkhead box A1 (FOXA1) plays an important role in several tumors. This study investigated the potential role of FOXA1 expression in thyroid tumors. We conducted a retrospective study of 110 thyroid lesions and tumors diagnosed during 1995-2018. The expression of FOXA1 was analyzed by immunohistochemistry on archival material. RESULTS: No FOXA1 immunostaining was observed in all cases of Graves' disease, Hashimoto's disease, multi-nodular goiter, and adenoma. FOXA1 expression was absent as well in all papillary and follicular carcinomas, Hurthle cell carcinoma, and undifferentiated sarcoma. Only three anaplastic carcinomas exhibited focally FOXA1 staining. However, FOXA1 was expressed in all medullary carcinomas. No significant correlation was found with all clinicopathological features (p > 0.05 for all). The pattern of FOXA1 staining was similar to that of calcitonin and chromogranin A (p = 0.04 and p = 0.003, respectively). CONCLUSIONS: FOXA1 is expressed mostly in all medullary thyroid carcinomas. Hence, FOXA1 could serve as an additional marker for refining the diagnosis of medullary thyroid carcinoma.

Ossifying fibromyxoid tumor of the trunk mimicking hydatid cyst: A case report.

INTRODUCTION: Ossifying fibromyxoid tumor (OFMT) is a rare lesion that generally occurs in the soft tissues of proximal limbs, head or neck and presents as a slowly growing mass. Abdominal or trunk locations are extremely rare. PRESENTATION OF CASE: We report a case of 50-year-old man who presented with a painless, slow growing epigastric mass for 5 years. Radiologic assessment revealed a well circumscribed median subcutaneous parietal mass lesion present in front of the xiphoid process suspicious of a calcified hydatid cyst. Diagnosis of OFMT was made on histopathological examination of the resected specimen. DISCUSSION: OFMT most often presents as a single swelling arising from the subcutaneous soft tissues or skeletal muscles of the extremities. Multifocal presentation is exceedingly rare. Radiologically, a peripheral shell of bone is seen in more than 50% cases. On MRI, myxofibrous stroma appears isointense to muscle on T1 and of intermediate to high signal intensity on T2. Surgical excision is the mainstay of treatment. Histologically, the tumor has a thick fibrous capsule with a complete or partial underlying layer of metaplastic woven or lamellar bone. Tumor is composed of uniform round, ovoid, or spindle-shaped cells arranged in nests and cords embedded in a variably myxoid and collagenous Alcian blue-positive stroma. On immunochemistry, the tumor cells are positive for S100 protein and desmin in 90% and 50% cases respectively. CONCLUSION: OFMT is a rare soft tissue tumor with malignant potential often misdiagnosed as a benign lesion. Complete surgical excision should be performed to prevent local recurrence.

Retroperitoneal unicentric Castleman's disease: A case report.

INTRODUCTION: Castleman's disease (CD) is an angio-follicular lymph node hyperplasia presenting as a localized or a systemic disease masquerading malignancy. The most common sites of CD are mediastinum, neck, axilla and pelvis. Unicentric CD in the peripancreatic region is very rare. PRESENTATION OF CASE: We report a case of the 34-year-old lady presenting with epigastric pain for 3 months. Abdominal imaging revealed a retroperitoneal mass arising from the pancreas suspected to be neuroendocrine tumor. Tumor markers were not elevated. Complete surgical excision was performed and patient had uneventful recovery. Pathologic findings demonstrated localized hyaline-vascular type of Castleman's disease. DISCUSSION: CD is a very rare cause for development of retroperitoneal mass. It is more frequent in young adults without predilection of sex. It can occur anywhere along the lymphoid chain. Abdominal and retroperitoneal locations usually present with symptoms due to the mass effect on adjacent organs. CD appears as a homogeneously hypoechoic mass on ultrasound and non-specific enhancing homogeneous mass with micro calcifications on computed tomography. Histologically, the hyaline vascular type demonstrates a follicular and inter-follicular capillary proliferation with peri-vascular hyalinization, with expansion of the mantle zones by a mixed inflammatory infiltrate of numerous small lymphocytes and plasma cells. The standard therapy of localized form is en bloc surgical excision as performed in our case. CONCLUSION: Unicentric CD in the peripancreatic region is difficult to differentiate from pancreatic neoplasm preoperatively. However, preoperative biopsy in cases of high clinical suspicion can help in avoiding extensive surgery for this benign disease.