Disappearance of "Elongated Pony Tail Sign" Following Chemoradiotherapy in a Case of Primary Cerebellopontine Angle Ependymoma With Spinal Drop Metastasis: 18 F-FDG PET/CT Scan Findings.

ABSTRACT: 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.

Role of 2-(fluorine-18) Fluoro-2-deoxy-D-glucose Positron Emission Tomography/Computed Tomography in Initial Staging and Bone Marrow Involvement Prediction in Patients with Newly Diagnosed Lymphoma in Correlation with Bone Marrow Study.

Background: Lymphoma is a common malignant proliferative disease in which bone marrow infiltration will upstage the disease and thus affect prognosis of the disease. As of now bone marrow biopsy is considered as a reference standard to find out bone marrow involvement in lymphoma. Performing an invasive and painful intervention in all newly diagnosed lymphoma patients is controversial. PET-CT is a non-invasive technique that gives functional information about the cells using the glucose metabolism. It can detect early bone marrow and extra medullary organ involvement which can lead to restaging of the disease. These advantages make PET-CT a valuable adjunct in diagnosis of lymphoma. Aims and Objectives: Our study aims to evaluate the usefulness of 18 F-FDG PET-CT, a non-invasive, semi quantitative whole body imaging technique for detection of early bone marrow and extra medullary organ involvement in lymphoma patients which in turn can obviate the need for bone marrow study (BMS). The primary objective of study is to categorise FDG uptake in bone marrow as diffuse /unifocal /multifocal / no uptake and to correlate pattern of FDG uptake to bone marrow study. Our study also assesses the role of FDG PET/CT in staging of lymphoma. Materials and Methods: Thirty patients with newly diagnosed lymphoma in the age group 18 to 75 years of both sexes within 3 months of diagnosis and who have not been started on any treatment was included in the study. Marrow uptake on FDG PET/CT has been categorized as diffuse, unifocal, multifocal and no uptake. Agreement between bone marrow study and FDG PET/CT has been assessed by reliability analysis using Cohen's kappa. Sensitivity, specificity, PPV, NPV of PET/CT in detecting marrow involvement have been calculated. Results: The sensitivity, specificity, PPV, NPV and accuracy of 18 F-FDG PET-CT in detecting marrow involvement of lymphoma cases are 86.6%, 77.7%, 68.4%, 91.3% and 80.9% respectively. 18 F-FDG PET-CT detected bone marrow involvement in 86.6% (13 out of 15 total positive cases) cases of lymphoma which included both HL and NHL. Reliability analysis using Cohen's kappa is used to test the agreement between bone marrow study and 18F-FDG PET/CT. k value of 0.6 was obtained which showed a moderate agreement between bone marrow study and 18F-FDG PET/CT in marrow assessment. Conclusion: 18F-FDG PET/CT is a highly sensitive imaging modality which can pick up extra-nodal organ and BMI in patients with lymphoma and can upstage the disease and alter treatment strategies. PET-CT cannot completely replace the bone marrow study. However, being an invasive painful procedure, BMB can be avoided in cases with unifocal or multifocal marrow involvement on PET-CT.

"Diffuse Hot Pleura" in a Case of Recurrent Squamous Cell Carcinoma of the Foot: 18 F-FDG PET/CT Findings.

ABSTRACT: Cutaneous squamous cell carcinoma (cSCC) is the second most common nonmelanoma skin cancer. Unlike basal cell carcinoma, regional lymph nodal metastases and subsequent distant site metastases are more common. Up to approximately 2% to 5% of cSCCs can result in distant metastases. Prognosis is dismal, and median survival is distinctly shortened in case of distant metastatic disease. Diffuse pleural metastases with distinctive overarching unilateral involvement are uncommon. Cutaneous SCC commonly metastasizes to lymph nodes, lungs, liver, bones, and skin. Diffuse unilateral pleural metastasis of cSCC of the foot is extremely rare. We report the case of a 54-year-old man with recurrent cSCC. On follow up restaging, 18 F-FDG PET/CT revealed diffuse nodular bipleural (visceral and parietal) hypermetabolic right pleural thickening, which was later biopsied and turned out to be diffuse pleural metastases from cSCC giving appearance of "hot pleura."

18F-Labeled Fluoro-2-Deoxyglucose Positron Emission Tomography and Computed Tomography Findings in a Case of Atypical Presentation of Adult Cutaneous T-cell Lymphoma.

Adult cutaneous T-cell lymphoma is an uncommon malignancy with poor prognosis and is usually seen in association with human T-cell lymphotropic virus type 1. We present the case of a 25-year-old female who gave a history of extensive whole-body polypoidal cutaneous and bilateral orbital and breast swellings. Biopsy was suggestive of cutaneous T-cell lymphoma and the patient was evaluated with 18F-labeled fluoro-2-deoxyglucose positron emission tomography and computed tomography for initial staging of the disease.

18F Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Findings in a Case of Metastatic Eccrine Porocarcinoma - An Extremely Rare Malignant Adnexal Tumor.

Porocarcinoma is a rare malignant neoplasm of eccrine sweat glands representing 0.005 to 0.1% of all cutaneous tumors. As eccrine porocarcinoma carries a high risk of recurrence and metastases, early diagnosis and management are crucial to lower mortality rate. We present the case of porocarcinoma in a 69-years-old woman who underwent 18F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) for staging the disease. PET/CT showed metabolically active multiple cutaneous lesions and also picked up lymph nodal and distant metastases to lungs and breast accurately. PET/CT is useful for accurate staging of the disease and for treatment planning.

Orbital Plasmablastic Lymphoma: A Rare Variant of Diffuse Large B-Cell Lymphoma Staged and Followed Up by 18F-FDG PET/CT.

ABSTRACT: Plasmablastic lymphoma (PBL) is a rare and aggressive variant of diffuse large B-cell lymphoma which is associated with HIV infection. Recently, it has also been reported in immunocompetent and solid organ transplant patients. PBL commonly presents in extranodal regions such as oral cavity, digestive tract, and skin. Orbital involvement by PBL is extremely rare with only few reports in the literature. We present a case of PBL involving the bilateral orbits in an immunocompetent patient with 1-year follow-up on 18F-FDG PET/CT scan.

Primary Biliary Tuberculosis Masquerading Cholangiocarcinoma in 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography.

Hepatobiliary involvement is a less common manifestation of abdominal tuberculosis. We present the case of a 42-year-old female who presented with fever, abdominal pain, and jaundice of 2 months duration. 18F-fluorodeoxyglucose positron emission tomography/computed tomography done for disease evaluation suggested the likely possibility of cholangiocarcinoma but excision biopsy from periportal lymph node later confirmed a granulomatous etiology and she was successfully treated with antitubercular therapy.

Diffuse White Adipose Tissue 18F-FDG Uptake-An Unusual Finding on 18F-FDG PET/CT.

ABSTRACT: Brown adipose tissue of cervical, supraclavicular, and paravertebral regions can show increased FDG uptake. But human white adipose tissue (WAT) shows negligible FDG uptake on 18F-FDG PET/CT scan. We present a case of carcinoma cervix treated with concurrent chemoradiation. 18F-FDG PET/CT shows altered biodistribution of FDG with intense FDG uptake throughout the WAT. Later on, patient confirmed taking herbal medication for herpes zoster infection, which could contain corticosteroids, resulting in enhanced WAT uptake of 18F-FDG.