RESUMO
Malakoplakia is a rare granulomatous tumor-like inflammatory condition, most frequently involving the genitourinary system and occurring in immunosuppressed patients. The gastrointestinal tract is the second most common site, where it is usually seen involving the colon. We report a case of malakoplakia presenting as a pancreatic mass. Imaging showed soft tissue along the pancreatic tail/greater curvature concerning for infiltrating tumor, but endoscopic ultrasound with biopsy showed malakoplakia. Our case discusses malakoplakia at an uncommon site, which was appropriately treated with antibiotics.
RESUMO
Recent literature indicates that adenocarcinomas of the cecum differ with respect to molecular alterations compared with noncecal proximal colon adenocarcinomas and that cecal tumor site may be a prognostically relevant variable. We compared molecular alterations, histopathologic features, and disease-specific survival in a series of 328 colonic adenocarcinomas identified over a 2-year period and stratified by tumor location (cecum, right colon, and left colon). Overall, cecal adenocarcinomas demonstrated the highest frequency of molecular abnormalities with 74% harboring either a KRAS exon 2 or 3 mutation, a BRAF mutation, or DNA mismatch repair protein deficiency. KRAS mutations were more frequently seen in the cecum compared with all other tumor sites (P=0.03). KRAS mutations were identified in 46% of cecal adenocarcinomas compared with only 25% of adenocarcinomas of the right colon (P=0.004). Cecal adenocarcinomas more frequently displayed adverse histopathologic features, in particular high tumor budding (31%), compared with tumors of the right colon (18%; P=0.04) and tumors of the left colon (17%; P=0.02). Overall stage was the most important independent predictor of disease-specific survival in the multivariable analysis; however, cecal tumor site and high tumor budding were also predictive of poor survival, particularly in patients with stage III or IV tumors. In conclusion, cecal adenocarcinomas are characterized by a high frequency of KRAS mutations compared with noncecal right colon tumors, frequently display high tumor budding, and may be a prognostically relevant variable, particularly in patients with stage III or IV disease.
Assuntos
Adenocarcinoma/genética , Adenocarcinoma/patologia , Biomarcadores Tumorais/genética , Neoplasias do Ceco/genética , Neoplasias do Ceco/patologia , Movimento Celular , Neoplasias do Colo/genética , Neoplasias do Colo/patologia , Mutação , Proteínas Proto-Oncogênicas p21(ras)/genética , Adenocarcinoma/mortalidade , Adenocarcinoma/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias do Ceco/mortalidade , Neoplasias do Ceco/cirurgia , Neoplasias do Colo/mortalidade , Neoplasias do Colo/cirurgia , Feminino , Predisposição Genética para Doença , Humanos , Masculino , Pessoa de Meia-Idade , Taxa de Mutação , Estadiamento de Neoplasias , Fenótipo , Estudos Retrospectivos , Adulto JovemRESUMO
Reduced CDX2 and cytokeratin 20 (CK20) expression in colorectal carcinoma with BRAF mutation and high-level microsatellite instability (MSI-H) has been well documented. The immunophenotype of BRAF-mutated microsatellite stable (MSS) colorectal carcinoma has not been reported. We analyzed 205 colorectal carcinomas including 28 BRAF-mutated MSS, 53 BRAF-mutated MSI-H, and 124 BRAF wild-type MSS tumors for CDX2, cytokeratin 7 (CK7), and CK20 immunohistochemical expression. CDX2 was scored semiquantitatively for both staining intensity and percent of tumor cells staining and a modified CDX2 H-score was calculated. Patients with BRAF-mutated MSS colorectal carcinomas were more frequently stage IV at presentation compared to patients with BRAF-mutated MSI-H colorectal carcinomas and BRAF wild-type MSS colorectal carcinomas (32% versus 8% versus 15%, P < .001). BRAF-mutated MSS colorectal carcinoma displayed reduced CDX2 expression compared to BRAF wild-type MSS colorectal carcinoma (75% versus 94%; mean CDX2 H-score 98 versus 150, P < .001). CK7 expression was more often identified in BRAF-mutated MSS colorectal carcinoma compared to both BRAF-mutated MSI-H colorectal carcinoma and BRAF wild-type MSS colorectal carcinoma (39% versus 6% versus 6%, P = .0001). BRAF-mutated MSI-H colorectal carcinomas were less often CK20 positive compared to BRAF-mutated MSS and BRAF wild-type MSS tumors (70% versus 93% versus 90%, P = 0.001). In summary, BRAF-mutated MSS colorectal carcinoma often displays reduced CDX2 and increased CK7 expression. Knowledge of this altered immunophenotype is important as patients with BRAF-mutated MSS colorectal carcinoma often present with metastatic disease and the altered tumor immunophenotype may lead to the erroneous assumption that origin from the colon/rectum is unlikely.