Background: Tick-Borne Encephalitis virus (TBEV) is a positive-sense single-stranded RNA virus belonging to the Flaviviridae family. TBEV transmission typically occurs through infected Ixodes tick bite or by consumption of unpasteurised milk from infected cattle. Case report: We report the clinical, neuroimaging, electroencephalogram (EEG), and laboratory (microbiological tests and spinal tap) data of a 6- year-old boy with Tick-borne encephalitis. Our patient presented with a biphasic course, initially with a myositis-like picture on his first admission to the emergency department, and after a few days with an encephalitic picture, resulting in a second hospitalization. EEG showed focal slow activity, while his brain magnetic resonance imaging (MRI) showed a signal abnormality, which completely resolved on repeat MRI after 3 months. Conclusion: To our knowledge, this is the youngest patient presenting with myositis in the first phase of Tick-borne encephalitis (TBE). In the presence of a biphasic clinical course, with previous myositis, aspecific MRI changes in the thalamic and midbrain regions and an EEG documenting slowed bioelectrical activity should prompt suspicion of TBEV infection.

We are reporting a rare case of primary gastric synovial sarcoma in a young male. Synovial sarcoma of the stomach is a very rare tumor. The common involved sites of occurrence of synovial sarcomas are upper and lower extremities. In the English literature, only 47 cases of primary synovial sarcoma of stomach have been reported. Spindle-shaped tumor cells are the basic content of synovial sarcomas with varying degrees of epithelial differentiation. The basic classification of synovial sarcoma depends on the histological pattern and the degree of differentiation and it is classified as monophasic, biphasic, and poorly differentiated. Synovial sarcoma presents with classical chromosomal translocation where they form fusion genes of SS18-SSX1, SS18-SSX2, and SS18-SSX4. Fluorescence in situ hybridization (FISH) and reverse transcription polymerase chain reaction (RT-PCR) are the molecular analysis techniques to detect these fusion genes. As the available literature support is limited, the role of adjuvant chemotherapy, radiation therapy, and intra-operative lymphadenectomy is still unclear. However, surgical resection with clear margin is the gold standard treatment.

This case report describes a 22-year-old man with a pharyngeal foreign body sensation arising from the left side of the postpharyngeal wall. Histological examination showed a biphasic pattern of epithelioid and spindle cells including glandular differentiation. The tumour was positive for vimentin and SS18-SSX, and the spindle cells were positive for bcl-2; in contrast, the epithelioid tumour cells were positive for pan-cytokeratin, epithelial membrane antigen and CD99. There was no INI-loss in tumour cells. Then, the presence of the SYT-SSX gene fusion was demonstrated by fluorescence in situ hybridization. In addition, androgen receptor gene somatic mutations were detected by next-generation sequencing. However, 6 months postoperatively, the patient had neither developed a recurrence nor received adjuvant radiotherapy and chemotherapy. Accurate diagnosis depends on morphological and immunohistochemical examination and a proper molecular analysis, and novel technologies can detect a wide variety of genetic alterations. Although androgen receptor somatic mutations cannot provide addition treatment at present, surgical resection with a clean margin and follow-up is an appropriate approach.

Some skin adnexal tumors display both epithelial and myoepithelial cell populations and can be broadly categorized as biphasic tumors. These include apocrine hidrocystoma, mixed tumor, adenomyoepithelioma (AME), and adenoid cystic carcinoma (ACC). Myoepithelioma is the myoepithelial cell-predominant type in this category. Cutaneous AME is exceedingly rare and usually has a benign prognosis, but it is considered to have the potential for local recurrence and metastasis. We report the case of a 57-year-old man with a 1-year history of an ulcerated nodule on his scalp. Microscopically, it was a defined cutaneous nodule with a focal lobulated architecture, composed of epithelial cells forming ducts and myoepithelial cells distributed around the ducts. In addition to these findings of typical AME, the present case focally revealed atypical features, such as increased mitotic activity (7/10 high power fields), invasive growth, and necrosis. However, cytological atypia was not significant. We conclusively diagnosed cutaneous AME with atypical features, suggesting malignant potential. Moreover, areas showing appearances similar to apocrine hidrocystoma, mixed tumor, myoepithelioma, and ACC were focally observed. We present a unique case of cutaneous AME exhibiting histopathological heterogeneity. The recognition of morphological variation could be helpful in appropriately diagnosing and treating AME of the skin.

Carcinosarcoma, also known as metaplastic carcinoma, is a rare and aggressive malignant tumor. We report a case of metaplastic carcinoma presenting as inflammatory carcinoma and provide a review of the related literature. A 38-year-old breastfeeding woman presented with concerns about a painful lump in her left breast. The symptoms had been present for two months. After admission to the hospital, the triple assessment revealed findings consistent with inflammatory carcinoma of the breast. The patient underwent modified radical mastectomy. Histopathological examination revealed a gray-white tumor with a biphasic pattern with features of ductal carcinoma as well as squamous and sarcomatous differentiation. On immunohistochemistry, the neoplastic cells were positive for cytokeratin and vimentin, and focally positive for smooth muscle antigen (SMA) and negative for estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor (HER-2/neu). Based on histological and immunohistochemical findings, the tumor was diagnosed as carcinosarcoma. Four of eighteen dissected axillary lymph nodes were positive for metastasis. Carcinosarcoma is often a triple-negative tumor. The lack of standardized treatment protocols frequently leads to poor prognosis and can pose a diagnostic dilemma; it should be part of the differential diagnosis for a case of carcinoma of the breast presenting as inflammatory carcinoma.

Localized biphasic MPeM is rare in clinical practice, we reviewed 8 cases of localized biphasic MPeM (including our present case), and summarized the clinical and imaging features of the disease.
We reported a 79-year-old man with chief complaint of a narrowing in the caliber of the stool for one year. A soft tissue shadow was occasionally found by CT examination in the right pelvic wall, and it was diagnosed as localized biphasic malignant peritoneal mesothelioma (MPeM) by postoperative pathology. Radical excision was performed and no radio-chemotherapy was applied. Nearly six years after surgery, the mass was significantly enlarged, and the neighboring tissues including rectum, prostate, seminal vesicle, and right ischial ramus were all infiltrated. The patient was in the end stage of cancer with poor prognosis.
The localized biphasic MPeM may show following characteristics: (1) with heterogeneous low-density and obscure margin; (2) with low incidence rate of ascites; (3) with few central hemorrhage and necrosis; (4) with few calcified structures; (5) with mild to moderate heterogeneous delayed enhancement on contrast-enhanced CT. The imaging characteristics can provide further information for the diagnosis of localized biphasic MPeM in the future.

Synovial sarcoma (SS) is an aggressive soft tissue tumor, which occurs predominantly in young adults. The SS can arise in almost any part of the body, especially in the lower extremity. The SS of head and neck accounts for 1.9-3.5% of all SS, however, the mass appears very extremely rare in the larynx. We report a case of a biphasic SS in the larynx. A 14-year-old boy appeared without apparent inducement with hoarseness, dyspnea, fever, cough, hemoptysis, pharyngeal foreign body sensation, dysphagia, odynophagia and other symptoms since nearly one month ago. The patient underwent partial laryngectomy and performed a wide surgical excision of the tumor with a free margin. Pathological examinations of the tumor specimen revealed an encapsulated and firm tumor lesion. The grayish-white to dark-brown mass was 8×6×4 cm, arising from the left of aryepiglottic fold. Histological examination showed the characteristic histomorphological features such as biphasic pattern of short spindle cells and epithelioid cells, including glandular differentiation. Immunohistochemically, staining for vimentin, bcl-2 and calponin were typically positive in the spindle tumor cells. Staining for CK was typically positive in the epithelioidtumor cells. Staining for EMA, CD99 and TLE-1 were typically positive in both the epithelioid and spindle tumor cells. The presence of SYT-SSX fusion gene from chromosomal translocation was detected by FISH in this case. Two months postoperatively, the patient received local radiotherapy. Combined treatment may be effective and the patient is alive without tumor recurrence in radiological and clinical examination after 18 months of follow-up.

Primary synovial sarcoma of the kidney is a very rare spindle cell neoplasm that occasionally displays epithelial differentiation. It occurs between 15-60 years of age with a mean of 35 years and a slight male predilection. Most of synovial sarcomas appear as relatively nonspecific soft tissue masses involving the kidney. This rare entity has some overlapping morphologic and immunohistochemical characteristics with other more common renal spindle cell neoplasms. Molecular tools add valuable diagnostic confirmation. We report a 56 year old male who presented to the emergency department with hematuria and abdominal pain. He had an abdominal CT-scan which showed a 6.6 cm enhancing right renal mass. Morphologic and immunohistochemical studies were directed towards synovial sarcoma with confirmation by SYT-SSX gene fusion using RT-PCR molecular technique. We reviewed the literature on the epidemiologic, histologic spectrum, immunophenotypic, clinical significance and prognosis and therapy.

Sarcomatoid carcinoma (SC) of the lung is a rare and aggressive biphasic lung tumor with a 5-year survival of 20%. Early detection and treatment is the only way to improve outcomes in patients with SC of the lung. We present a case of primary SC identified early based on high suspicion. A 56-year-old female with a history of chronic obstructive pulmonary disease (COPD) presented with hemoptysis and exertional dyspnea. Chest X-ray revealed right upper lobe (RUL) opacity and patient was started on antibiotics for pneumonia. Due to the persistence of hemoptysis, a computed tomography scan was performed which showed RUL bronchiectasis with scattered nodular opacities suggestive of an infectious process. The patient underwent bronchoscopy which revealed a pedunculated mass in the RUL biopsy of which was consistent with poorly differentiated SC. Positron-emission tomography scan revealed Flourdeoxyglucose-avid right peri-hilar mass and another nodule in the RUL. The patient was not a surgical candidate because of severe COPD and was started on chemoradiation therapy. SC of the lung can have various presentations and is usually detected at a later stage and hence, difficult to treat. Our case highlights the importance of critical thinking and prompt diagnostic evaluation in high-risk patients with localized bronchiectasis even without an obvious lung mass on imaging.

Classic biphasic pulmonary blastoma (CBPB) is a rare and aggressive type of non-small cell lung carcinoma (NSCLC) presenting in adults in the fourth to fifth decade. The prognosis is poor and after surgical resection, therapeutic options are often limited. ROS1 is a proto-oncogene receptor tyrosine kinase that has been identified in some types of NSCLC. We report a case of a 36-year-old woman with CBPB, which was subsequently found to have a ROS1 rearrangement. This is the first reported case of a ROS1-rearranged CBPB. This finding has therapeutic implications as these tumors have the potential to be treated with receptor tyrosine kinase inhibitors.