Accompanying a semi-nested PCR assay to support histopathology findings of fungal keratitis in formalin-fixed paraffin-embedded corneal samples.

BACKGROUND: Fungal species are responsible for 40%-50% of all microbial keratitis cases. Due to the low amount of extracted DNA in ocular Formalin-fixed Paraffin-embedded (FFPE) samples, selecting a reliable molecular method is a substantial issue in this field. METHODS: Sixty-six samples were collected via the penetrating keratoplasty (PK) technique. Histopathology assays were performed using hematoxylin-eosin (H&E) and periodic acid Schiff (PAS) staining methods. The ITS1/ITS4 and ITS1/ITS2 primer pairs were used in a semi-nested polymerase chain reaction (PCR) to target the universal internal transcribed spacer (ITS) region. Some PCR results were validated through sequencing. RESULTS: Fungal DNA was detected in 44 of 66 samples (66.7%), and histopathology was positive for 41 of 66 samples (62.1%). Of 41 histopathologically proven fungal-positive cases, 39 were PCR-positive (95%). Moreover, of 44 PCR-positive samples, 39 (88.6%) were histopathology-positive, and 5 (11.3%) were histopathology-negative. Totally in 39 cases (59%), both histopathology and PCR yielded positive results. The Kappa agreement rate between the two diagnostic methods, including histopathology and PCR, was 0.77. Sensitivity, specificity, positive predictive value, and false predictive value were reported as 88.64%, 90.9%, 95.12%, and 80%, respectively. CONCLUSION: As we reached the acceptable Kappa agreement rate, we concluded that applying the semi-nested PCR assay is a promising method for supporting the evidence by histopathology. Finally, we suggest targeting more specific gene regions using primer pairs that amplify smaller amplicon sizes and surveying novel molecular methods such as NGS to achieve higher sensitivity and Kappa agreement rates.

An asymptomatic huge primary retroperitoneal pseudocyst: a case report and review of the literature.

BACKGROUND: Retroperitoneal non-pancreatic or idiopathic pseudocysts are very rare lesions. This case report aimed to present our patient and to check all the available literature on this kind of rare disease. CASE PRESENTATION: Our patient was a 67-year-old Iranian man admitted with mild abdominal discomfort for three months. Ultrasonography and CT scan revealed a huge cystic structure within the retroperitoneal space. The lesion was excised through midline laparotomy and opening of the retro-peritoneum. The histopathology of the cyst wall revealed a benign cystic lesion with no epithelial lining. A histologic diagnosis of non-neoplastic retroperitoneal pseudocyst was made. CONCLUSION: The primary non-pancreatic retroperitoneal pseudocysts are rare lesions and have to be distinguished from other differential diagnoses of retroperitoneal lesions, and a surgeon should be aware of the possible occurrence of these lesions with unknown origin. Surgical excision is the only way to exclude malignancy and confirm the diagnosis.

Esophageal leiomyoma and simultaneous overlying squamous cell carcinoma: a case report and review of the literature.

BACKGROUND: Squamous cell carcinoma is the most common epithelial tumor of the esophagus. Upper endoscopy with multiple minimally invasive biopsies should be performed to confirm the diagnosis. Leiomyoma of esophagus is rare, but it's the most common benign submucosal mesenchymal tumor of the esophagus. The simultaneous occurrence of an overlying epithelial lesion and a mesenchymal lesion is very rare. This study aims to show a case operated due to squamous cell carcinoma of esophagus that was postoperatively diagnosed with coexistent esophageal leiomyoma and give a clear overview of the existing literature on it. CASE PRESENTATION: The patient was a 41-year-old woman who underwent three field esophagectomy (McKeown). Pathological evaluation was done, and the patient had poorly differentiated squamous cell carcinoma and multiple leiomyomas. A leiomyoma was found with an invading overlying squamous cell carcinoma. CONCLUSION: It is concluded that esophageal carcinomas may coexist with leiomyomas; preexisting benign tumors may have played an important role in the development of the carcinoma by inducing constant stimulation of the overlying mucosa; endoscopic ultrasonography is recommended to avoid overestimating the extent of tumor invasion and the resultant aggressive radical surgery. As the developing countries had limited equipment, esophageal resection could be the modality of choice in the treatment.