Askin tumor: CT and FDG-PET/CT imaging findings and follow-up

Askin's Tumor a Rare Clinical Entity of Thoracopulmonary Region Cresenting as a Case of Paraparesis: Findings on 18F-FDG PET/CT

Askin's tumors are rare malignant neoplasms located in the thoracopulmonary region and mainly occur in children and adolescents. In this report, we describe a case of histologically proven Askin's tumor in a 24-year-old male. The patient was admitted with a history of 3-month lower back pain and with a rare presentation of paraparesis.

Askin Tumor - Presenting as a Case of Paraparesis: A Rare Clinical Entity. Case Report and Findings on 18F-Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography

Askin tumors are rare malignant neoplasms located in the thoracopulmonary region and mainly occur in children and adolescents. In this report, we describe a case of histologically proven Askin's tumor in a 24-year-old male. The patient was admitted with a history of 3-month lower back pain and with a rare presentation of paraparesis.

Radiological and pathological diagnosis of an incidental Askin tumor

A 53-year-old male with no significant past medical history presented with an acute traumatic fracture of his thumb. Preoperative chest radiograph before K-wire fixation demonstrated an incidental 9 cm opacity of the left lung. Chest computed tomography revealed a 6.3 cm aggressive appearing pleural-based mass with erosion and destruction of the underlying rib. The patient underwent percutaneous biopsy with interventional radiology, and pathology revealed a small round blue cell tumor with positive CD99 staining and a FUS-ERG chromosomal translocation. The patient was diagnosed with Askin tumor, a peripheral primitive neuroectodermal tumor of the thoracopulmonary region belonging to the Ewing sarcoma tumor family. Computed tomography and magnetic resonance imaging of Askin tumors may show features such as a heterogeneous soft tissue mass, pleural effusion, rib destruction, hemorrhage, necrosis, and cystic degeneration. Askin tumors typically exhibit the EWS-FLI1 fusion mutation, although FUS-ERG chromosomal translocation has been described. Both rarity and variability of Askin tumors present a diagnostic challenge for clinicians. Collaborative effort amongst radiologists and pathologists is essential for diagnosis.

pH-dependent and cathepsin B activable CaCO3 nanoprobe for targeted in vivo tumor imaging

Background: The intraoperative visualization of tumor cells is a powerful modality for surgical treatment of solid tumors. Since the completeness of tumor excision is closely correlated with the survival of patients, probes that can assist in distinguishing tumor cells are highly demanded.

Purpose: In the present study, a fluorescent probe JF1 was synthesized for imaging of tumor cells by conjugating a substrate of cathepsin B (quenching moiety) to Oregon Green derivative JF2 using a self-immolative linker.

Methods: JF1 was then loaded into the folate-PEG modified CaCO₃ nanoparticles. The folate receptor-targeted, pH-dependent, and cathepsin B activable CaCO₃ nanoprobe was test in vitro and in vivo for tumor imaging.

Results: CaCO₃ nanoprobe demonstrated good stability and fast lighting ability in tumors under low pH conditions. It also showed lower fluorescence background than the single cathepsin B dependent fluorescent probe. The pH-dependent and cathepsin B controlled “turn-on” property enables precise and fast indication of tumor in vitro and in vivo.

Conclusion: This strategy of controlled drug delivery enables in vivo imaging of tumor nodules with a high signal-to-noise ratio, which has great potential in surgical tumor treatment.

18F-FDG PET/CT in a cardiac metastasis in a patient with history of malignant neuroectodermal tumour of the chest wall: Case report and review of the literature

The case presented is a 25-year-old male with a malignant neuroectodermal tumour on the left chest wall (Askin tumour), treated with surgery after neoadyuvant chemotherapy and followed by consolidation chemotherapy. After 9 years of disease free survival, the patient developed an acute pulmonary embolism. The echocardiogram, thoracic CT, and cardiac MRI scans revealed a mass in the right atrium. Recurrence of an Askin tumour versus an atrium myxoma was suspected. ¹⁸F-FDG PET/CT showed an intense hypermetabolic right atrium mass with extension to the right ventricle highly suggestive of malignancy. The result of the histopathology examination after biopsy and subsequently exeresis of the right atrium mass was consistent with a metastasis of the primary tumour.