Pneumatocele formation in a fatal adult pneumonia patient coinfected with Streptococcus pyogenes emm-type 3 and influenza A: a case report.

BACKGROUND: A pneumatocele is a transient thin-walled lesion and rare complication in adult pneumonia. A variety of infectious pathogens have been reported in children with pneumatoceles. We report the first case of adult pneumonia with pneumatocele formation that is likely caused by Streptococcus pyogenes and coinfection with influenza A virus. CASE PRESENTATION: A 64-year-old Japanese man presented with a one-week history of fever, sore throat, and arthralgia. He was referred to our university hospital for respiratory distress. He required mechanical ventilation in the intensive care unit (ICU). Bacterial culture detected S. pyogenes in the bronchoscopic aspirates, which was not detected in blood. Although a rapid influenza antigen test was negative, an influenza A polymerase chain reaction (PCR) test was positive. Therefore, he was diagnosed with coinfection of influenza A and group A streptococcus (GAS) pneumonia complicated by probable streptococcal toxic shock syndrome. A chest radiograph on admission showed diffuse patchy opacification and consolidation in the bilateral lung fields. Multiple thin-walled cysts appeared in both middle lung fields on computed tomography (CT). On the following day, the bilateral cysts had turned into a mass-like opacity. The patient died despite intensive care. An autopsy was performed. The pathology investigation revealed multiple hematomas formed by bleeding in pneumatoceles. CONCLUSIONS: There have been no previous reports of a pneumatocele complicated by S. pyogenes in an adult patient coinfected with influenza A. Further molecular investigation revealed that the S. pyogenes isolate had the sequence type of emm3.

Tracheal Paraganglioma: A Case report and Review of the Pertinent Literature.

The trachea is a sporadic origin of paraganglioma. The purpose of the present study was to identify the features of tracheal paraganglioma and reveal the effectiveness of computed tomography (CT) and magnetic resonance imaging (MRI) by reviewing both previous and current cases. In cases of tracheal tumors, we need to consider the bleeding risk associated with a biopsy, as the tumor may be paraganglioma, which is hypervascular. If a biopsy is not available, then CT and MRI can aid in making a pre-operative diagnosis. MRI in particular is useful for long-term observations.

CT and MRI findings of thymic carcinoid.

OBJECTIVE: To evaluate the CT and MRI findings of thymic carcinoid and to compare these findings with previously published findings of thymoma. METHODS: 11 cases of pathologically proven thymic carcinoid were reviewed retrospectively. Three patients had typical carcinoid, and eight patients had atypical carcinoid. The characteristics of the tumours and related thoracic abnormalities were assessed in each case on CT and/or MRI by two chest radiologists. The final decisions on the findings were reached by consensus. RESULTS: Thymic carcinoids were more likely to have a large mass (ranging from 18 to 105 mm), irregular contours (n = 8), heterogeneous intensity on T2 weighted images (n = 6; eight patients underwent MRI), heterogeneous enhancement (n = 9) and local invasion (n = 7). A necrotic or cystic component was identified in seven patients (one typical carcinoid and six atypical carcinoids). Lymphadenopathy was seen in four patients. Septum, capsule, haemorrhage and calcification were seen in three patients, two patients, two patients and one patient, respectively, with atypical carcinoid. CONCLUSION: Thymic carcinoids tend to have a high prevalence of large masses, irregular contours, heterogeneous intensity on T2 weighted images, heterogeneous enhancement and local invasion on CT and/or MRI. A necrotic or cystic component is often seen in atypical carcinoid. Advances in knowledge: Radiologic features of thymic carcinoid mimic those of high-risk thymomas and/or thymic carcinomas.

The MRI findings in a case of ovarian mucinous borderline tumor mimicking a serous surface borderline tumor.

Exophytic papillary growth from the surface epithelium is one of the features suggesting serous surface borderline tumors of the ovary in which magnetic resonance imaging (MRI) typically shows a hyperintense papillary mass with a hypointense internal branching structure on T2-weighted images. We herein report a case of an endocervical-like mucinous borderline tumor of the ovary, which showed an exophytic papillary growth pattern on MRI as well as pathology. Such a growth pattern is known to be characteristic of serous borderline tumors, but it should be noted that it could also be a finding in mucinous borderline tumors.