BACKGROUND: Testicular metastasis from malignant solid tumors is extremely rare. It is usually found by chance during autopsy or pathological examination of testicular specimens. Therefore, we consider it necessary to report our patient\'s case of testicular metastasis from colon cancer.
METHODS: We report a 61-year-old Han Chinese male patient who presented to our clinic with progressive painless swelling of the right testicle for 2 years. Positron emission tomography-computed tomography scans showed increased 18F-fluorodeoxyglucose metabolism in the right testicle, possibly owing to distant metastasis. His previous medical history suggested that he had undergone laparoscopic-assisted right hemicolectomy for ascending colon cancer 4 years ago. Considering the ascending colon cancer metastasis to the right testicle, we performed a right radical testicular resection through an inguinal approach. Postoperative histological examination showed intestinal metastatic adenocarcinoma.
CONCLUSIONS: Colon cancer metastasis to the testes is uncommon. The clinical and imaging manifestations of this tumor are nonspecific, so the diagnosis relies on postoperative pathology. If testicular metastasis is found, treatment principles for advanced colon cancer should be followed.

Primary cardiac angiosarcomas are extremely rare, highly aggressive tumours with rapid progression and high metastatic capability. More than 60% of tumours are detected after the onset of a metastatic disease. In the two cases presented, we demonstrate the role of muti-modality imaging in the diagnosis of the lesion and provide valuable input in prognosticating the disease burden. In both cases, the diagnosis was suspected initially by imaging, based on radiological observations, before the final histopathology confirmation was made. Positron emission tomography- (PET-CT) was a critical component of the diagnostic workup for the detection of disease extent and volume of total disease burden. Hence, PET-CT imaging should be performed in all aggressive appearing cardiac tumours. In view of misleading clinical presentation, we suggest that aggressive workup to be performed in suspected patients. Young patients presenting with vague symptoms and those with recurrent, unresolving, unexplained pericardial effusion deserves special consideration.

Panniculitis is an inflammation that occurs in subcutaneous adipose tissue. Panniculitis includes physical panniculitis (e.g., traumatic) and infectious panniculitis (e.g., bacterial, fungal, subcutaneous panniculitis-like T cell lymphoma [SPCTL], etc.). Accurate diagnosis is crucial due to similar clinical presentation of all types of panniculitis. Here, we report a case of SPCTL which was initially diagnosed with traumatic panniculitis. A 15-year-old male patient was admitted to a previous hospital due to a progressively enlarged right flank and inguinal mass after an abdominal bruise. He was initially diagnosed with traumatic panniculitis, but the mass expanded throughout the chest and abdomen accompanied by a fever of over 11 months. Computed tomography (CT) revealed a subcutaneous mass in the anterior chest and abdominal wall. Fludeoxyglucose F18 (FDG) uptake was observed at those lesions using FDG-positron emission tomography (PET). A biopsy of the mass lesion was performed, during which SPCTL was diagnosed based on pathological examination. He was initially treated with prednisolone and cyclosporine A for two weeks. His fever went down, but subcutaneous mass in the chest and abdominal wall persisted. Therefore, he received a cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) regimen. After 6 courses of CHOP, CT revealed no disease evidence. He remained in complete remission at 30 months of therapy.

Muir-Torre syndrome (MTS) is a rare genetic disorder, considered a subtype of Lynch syndrome, that causes sebaceous cutaneous tumors and increases the risk of internal visceral tumors. We present a case of a 63-year-old male with a history of MTS with sebaceous tumors, colorectal, and urothelial cancers who underwent fluorine-18-deoxyglucose positron emission tomography/ computed tomography [18F]FDG PET/CT to follow-up on multiple [18F]FDG avid skin lesions and right pelvic lymph nodes. Although few reports are available detailing the utility of [18F]FDG PET/CT in this rare disease, this modality appears useful, and superior, to computed tomography in the diagnosis and follow-up of MTS.

BACKGROUND: The diagnostic complexities that arise in radiographic distinction between ectopic pleural thymoma and other thoracic neoplasms are substantial, with instances of co-occurring T-cell lymphocytosis and osseous metastasis being exceedingly rare.
METHODS: A 51-year-old woman was admitted to our hospital with dyspnea and chest pain. Upon imaging examination, she was found to have diffuse and nodular pleural thickening on the left side, collapse of the left lung and a compression in the second thoracic vertebrae. All lesions showed significant 18F-FDG uptake on 18F-FDG PET/CT examination. Furthermore, she exhibited T-cell lymphocytosis in her peripheral blood, lymph nodes, and bone marrow. After ruling out malignant pleural mesothelioma (MPM), lung cancer with pleural metastasis, and T-cell lymphoma, the definitive diagnosis asserted was ectopic pleural thymoma with T-cell lymphocytosis and bone metastasis.
CONCLUSIONS: Physicians need to expand their knowledge of the imaging features of ectopic pleural thymoma. Cases with T-cell lymphocytosis may exhibit increased aggressiveness and prone to bone metastasis.

Tuberculosis (TB) is an airborne infectious disease caused by Mycobacterium tuberculosis (MTB). Although it typically affects the lungs (pulmonary TB), one-fifth of TB cases present as extrapulmonary TB. The diagnosis of extrapulmonary TB is often overlooked due to its atypical clinical and radiological manifestations. Differentiating TB from neoplastic conditions poses significant challenges. A 33-year-old female patient was admitted to the emergency clinic with shortness of breath, cough, and abdominal pain. Postero-anterior chest X-ray revealed massive pleural effusion leading to mediastinal shift. With a preliminary diagnosis of malignant pleural effusion, a pleural catheter was inserted, and the patient was referred for a positron emission tomography (PET/CT) to assess the primary site and the optimal location for a biopsy. The PET/CT revealed asymmetric soft tissue thickening on the left side of the nasopharynx, and increased fluorodeoxyglucose (FDG) uptake in the left cervical lymph nodes raised suspicion regarding primary nasopharyngeal cancer. Additionally, there was an increased FDG uptake observed in the mass lesion located in the right upper lobe, mediastinal lymph nodes, pleural surfaces in the left hemithorax, perihepatic areas, and peritoneum, indicating diffuse metastatic disease. Tuberculosis diagnosis was confirmed through biopsies demonstrating granulomatous inflammation in the lung and nasopharynx, along with culturing MTB from pleural effusion. Positron emission tomography played a crucial role in identifying sites of TB involvement. Despite its rarity, healthcare professionals should consider nasopharyngeal TB as a potential diagnosis when evaluating nasopharyngeal masses.

UNASSIGNED: Primary skeletal muscle lymphoma is rare. We describe 18 F-FAPI-42 and 18 F-FDG PET/MRI findings in a case of primary peripheral T-cell lymphoma of the skeletal muscles with brain involvement. The multiple skeletal muscle tumors and one larger cerebral tumor showed intense FDG uptake and mild to moderate FAPI uptake. FDG PET was superior to FAPI PET in delineating the muscle tumors because of significantly higher FDG uptake of the muscle tumors than FAPI uptake. FAPI PET was superior to FDG PET in delineating the cerebral lesion because of a very low background FAPI activity in the brain parenchyma.

BACKGROUND: To demonstrate and analyze the 18F-FDG positron emission tomography/computed tomography (PET/CT) findings in this rare nevoid basal cell carcinoma syndrome (NBCCS).
METHODS: A 71-year-old woman with the left invasive breast cancer was treated with hormone therapy for six months and underwent the 18F-FDG PET/CT examination for efficacy evaluation. 18F-FDG PET/CT revealed the improvement after treatment and other unexpected findings, including multiple nodules on the skin with 18F-FDG uptake, bone expansion of cystic lesions in the bilateral ribs, ectopic calcifications and dilated right ureter. She had no known family history. Then, the patient underwent surgical excision of the all skin nodules and the postoperative pathology were multiple basal cell carcinomas. Finally, the comprehensive diagnosis of NBCCS was made. The patient was still in follow-up. Additionally, we have summarized the reported cases (n = 3) with 18F-FDG PET/CT from the literature.
CONCLUSIONS: It is important to recognize this syndrome on 18F-FDG PET/CT because of different diagnoses and therapeutic consequences.

UNASSIGNED: Ependymomas are rare glial tumors that commonly arise from the lining cells of ventricular system and constitute ~10% of intracranial pediatric malignancies. The incidence of ependymoma in adults is rare. Due to close approximation with the ventricular system, subtentorial ependymomas are more prone to show cerebrospinal fluid metastasis compared with supratentorial ependymomas. We present a case of subtentorial cerebellopontine angle ependymoma with diffuse spinal drop metastases showing \"elongated pony tail appearance\" in a 69-year-old man with complete metabolic response on 18 F-FDG PET/CT imaging following chemoradiotherapy.

UNASSIGNED: Solitary mixed squamous cell and glandular papilloma of the lung is an extremely rare benign neoplasm. We describe FDG PET/CT findings in a case of solitary mixed squamous cell and glandular papilloma of the lung with high serum carcinoembryonic antigen level (63.3 ng/mL; reference, <5 ng/mL). The tumor showed intense FDG uptake with SUVmax of 23.8 mimicking lung cancer.