Background and aim Recent studies have proposed that commensal bacteria might be involved in the development and progression of gastrointestinal disorders such as colorectal cancer (CRC). Therefore, in this study, the relative abundance of Fusobacterium nucleatum, Bacteroides fragilis, Streptococcus bovis/gallolyticus, and Enteropathogenic Escherichia coli (EPEC) in CRC tissues, and their association with clinicopathologic characteristics of CRC was investigated in Iranian patients. Moreover, the role of these bacteria in the CRC-associated mutations including PIK3CA, KRAS, and BRAF was studied. Method To these ends, the noted bacteria were quantified in paired tumors and normal tissue specimens of 30 CRC patients, by TaqMan quantitative Real-Time Polymerase Chain Reaction (qPCR). Next, possible correlations between clinicopathologic factors and mutations in PIK3CA, KRAS, and BRAF genes were analyzed. Results In studied samples, B. fragilis was the most abundant bacteria that was detected in 66 and 60% of paired tumor and normal samples, respectively. Furthermore, 15% of the B. fragilis-positive patients were infected with Enterotoxigenic B. fragilis (ETBF) in both adenocarcinoma and matched adjacent normal samples. F. nucleatum was also identified in 23% of tumors and 13% of adjacent normal tissue samples. Moreover, the relative abundance of these bacteria determined by 2-ΔCT was significantly higher in CRC samples than in adjacent normal mucosa (p < 0.05). On the other hand, our findings indicated that S. gallolyticus and EPEC, compared to adjacent normal mucosa, were not prevalent in CRC tissues. Finally, our results revealed a correlation between F. nucleatum-positive patients and the KRAS mutation (p = 0.02), while analyses did not show any association between bacteria and mutation in PIK3CA and BRAF genes. Conclusion The present study is the first report on the analysis of different bacteria in CRC tissue samples of Iranian patients. Our findings revealed that F. nucleatum and B. fragilis might be linked to CRC. However, any link between gut microbiome dysbiosis and CRC remains unknown.

Severe COVID‐19 patients complicated with aspergillosis are increasingly reported. We present a histopathological proven case of fatal COVID‐19–associated pulmonary aspergillosis (CAPA), due to Aspergillus flavus . This report and existing published literature indicate diagnostic challenges and poor outcomes of CAPA in ICU patients.

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Papillary thyroid carcinoma (PTC) represents the most common primary malignant thyroid lesion in all age groups. As diagnosis of PTC could be challenging in some cases and borderline nuclear features could be seen in some benign mimickers, several immunohistochemical markers are proposed to be helpful for making the correct diagnosis. In this study the authors investigated the diagnostic value of transmembrane glycoprotein (TROP2) for differentiating PTC from other thyroid follicular lesions. A total of 155 total thyroidectomy specimens including 84 cases of PTC and 71 cases of non-PTC were investigated. Among non-PTC group, 45 cases were follicular neoplasms and 26 cases were Hashimoto thyroiditis. TROP2 expression was observed in 82 of 84 cases of PTC group. In contrast only 5 cases of non-PTC group, all from Hashimoto thyroiditis specimens, showed positive expression. The sensitivity, specificity, positive predictive value, and negative predictive value of TROP2 for diagnosis of PTC was 98%, 93%, 94%, and 97%, respectively. The authors concluded that high sensitivity and specificity of TROP2 as well as its uniform negative reaction in follicular adenoma and carcinoma makes it a valuable immunohistochemical marker for diagnosis of PTC.

Background: Idiopathic granulomatous mastitis (IGM) is a rare benign inflammatory breast condition, mostly affecting women of reproductive age within a few years of pregnancy. Due to diverse clinical and radiologic features, IGM can mimic a vast spectrum of breast conditions. Therefore, histological findings are one of the most essential bases of diagnosis.  Methods: A literature search was performed to review the characteristics of IGM with an emphasis on histopathological features in English sources from 2010 to 2022. The key words used for PubMed database search were “breast”, “granulomatous mastitis”, “histopathology”, and “pathology.” Results: In total, 192 articles were retrieved, from which 38 most relevant manuscripts were selected for this review article. Conclusion: The diagnosis of IGM depends on clinical, radiologic, and pathologic findings. Palpable mass is the most frequent complaint. An irregular hypoechoic mass with varying degrees of posterior phenomena is the most common sonographic finding. Histologically, IGM is characterized by a non-caseating lobulocentric granulomatous inflammation; composed of tight aggregates of epithelioid histiocytes with or without multinucleated giant cells. At times, the presence of cystic empty vacuoles lined by neutrophils is noted that is commonly associated with cystic neutrophilic granulomatous mastitis (CNGM), a variant of IGM. Atypical findings for IGM includes: The presence of atypia and/or malignancy, caseous necrosis, marked eosinophilic infiltration, absence of granulomatous inflammation, etc.

Background: Low-grade fibromyxoid sarcoma is a rare painless neoplasm that primarily grows in young adults' proximal extremities and trunks. The lungs are infrequent sites for this type of sarcoma.Case Presentation: We reported a 26-year-old female that presented with a chief complaint of chest pain from a few months ago to Kasra hospital, Tehran, Iran, in August 2021. Chest computed tomography (CT) showed a hypodense mass with a well-defined margin measuring 9.3 cm in the left upper lobe and multiple hypodense lesions with a lobulated appearance with a total diameter of 15.5 Â 13.5 cm in the left lower lobe of the lung. Conclusion:This is the largest case of primary pulmonary low-grade fibromyxoid sarcoma (30 Â 28 Â 7 cm), which seemed unresectable at first evaluation. Due to the extent of the tumor, left pneumonectomy was performed, leading to attenuation of symptoms and no recurrence at a six-month follow-up.

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