Prathamesh Joshi

Unexpected visitor on FDG PET/CT--brown adipose tissue (BAT) in mesentery in a case of retroperitoneal extra-adrenal pheochromocytoma: is the BAT activation secondary to catecholamine-secreting pheochromocytoma?

Fused positron emission tomography-computed tomography (PET/CT) technology has enabled the determination that nonmalignant fluorodeoxyglucose (FDG) uptake is observed in brown adipose tissue (BAT). FDG uptake in BAT is a known potential source of false-positive interpretations for PET. The typical locations of BAT include neck, supraclavicular area, mediastinum, and paravertebral intercostal spaces. Examples of atypical locations for BAT include posterior neck, left paratracheal area, axillae, perirenal area, and retrocrural area. We report PET/CT findings in a young male patient with malignant retroperitoneal extra-adrenal pheochromocytoma, who demonstrated FDG uptake in BAT at multiple locations including mesenteric BAT. We also propose catecholamine-secreting pheochromocytoma as a possible cause of BAT activation in our case.

Lymphadenopathy resulting from acute toxoplasmosis mimicking relapse of non-Hodgkin's lymphoma on fluorodeoxyglucose positron emission tomography/computed tomography

We report a case documenting fluorodeoxyglucose (FDG) accumulation in cervical, supraclavicular and axillary lymph nodes resulting from acute toxoplasmosis. A 50-year-old Indian female with history of non-Hodgkins lymphoma (NHL) of left breast, postchemotherapy status, was found to have hypermetabolic right cervical, supraclavicular and axillary lymph nodes on a surveillance FDG positron emission tomography/computed tomography (PET/CT) scan. Her previous two PET/CT scans were unremarkable with no evidence of metabolically active disease. Therefore, a differential diagnosis of relapse of NHL versus infectious/inflammatory pathology was raised in the report. Biopsy of axillary lymph node demonstrated features characteristic of toxoplasmosis. The serological test results were also compatible with acute toxoplasmosis infection. Infective and inflammatory diseases are known to accumulate FDG, resulting in false positives for malignancy. This case demonstrates lymph nodal toxoplasmosis as a potential cause of false positive FDG PET/CT findings in patients with known malignancy and highlights the importance of histopathological and laboratory correlation for the accurate interpretation of FDG PET/CT scans.

Mortui vivos docent - the dead teach the living: 18-flurodeoxyglocose positron emission tomography-computed tomography findings in a case of intravascular B cell lymphoma

Intravascular large B-cell lymphoma is a rare and aggressive variant of diffuse large B-cell non-Hodgkins lymphoma. Its atypical presentation often delays the diagnosis and due to its aggressive behavior, the diagnosis is made post-mortem in half of the cases. We present FDG PET/CT findings in a case of IVLCL. In our case, the report of the patients bone marrow biopsy after death of the patient revealed the presence of IVLCL. After availability of final diagnosis, we reviewed the literature and a better explanation of the FDG PET/CT findings could be obtained. We describe this case, to call for heightened awareness in physicians for the rare but possible diagnosis of IVCLL, particularly in an elderly patient who presents with fever of unknown origin and demonstrates similar FDG PET/CT findings. Considering the characteristic scan findings described in our patient and other cases in literature, FDG PET/CT can be used in suspected cases of IVLCL for early diagnosis of this rapidly fatal malignancy.

Dual ectopic thyroid - noninvasive diagnosis on radionuclide thyroid scan with SPECT/CT correlation: A case report and brief review of literature

Indian Journal of Endocrinology and Metabolism / Mar-Apr 2013 / Vol 17 | Issue 2 359 rheumatica is a clinical syndrome characterized by pain and stiffness in the neck, shoulders, and hips, fatigue, weight loss and low‐grade fever and also rarely presented as a paraneoplastic manifestation. There are no specific diagnostic tests for PMR.[3] Cancer‐associated rheumatic disorders may represent a paraneoplastic phenomenon, i.e., occur at a distance from the primary tumor or metastases and be induced by the malignancy through mediators such as hormones, peptides, and antibodies. Case reports present a possible association of polymyalgia rheumatica with breast cancer, colon cancer, lymphoma, acute myeloid leukemia, prostate cancer.[2,4,5] Association between parathyroid cancer and PMR has not been reported in the literature previously. We want to emphasize that PMR may present as the first sign of parathyroid carcinoma.

An Unusual Case of Extraosseous Accumulation of Bone Scan Tracer in a Renal Calculus - Demonstration by SPECT-CT

Extraosseous localization of radioisotope, used in bone scan, in a variety of physiological and pathological conditions is a well-known phenomenon. The causes of extraosseous accumulation of bone-seeking radiotracers should be kept in mind when bone-imaging studies are reviewed to avoid incorrect interpretations. We report an extremely rare occurrence of extraosseous accumulation of bone scintigraphy tracer in a renal calculus, in a patient with adenocarcinoma of prostate, that was demonstrated by Single Photon Emission Computed Tomography and Computed Tomography (SPECT-CT) fusion imaging.

Malignant amelanotic melanoma - A diagnostic surprise: Flurodeoxyglocose positron emission tomography-Computed tomography and immunohistochemistry clinch the ′final diagnosis′

Amelanotic melanoma is a rare malignancy and the prognosis is usually poorer than that of pigmented melanomas, because of delay in establishing the correct diagnosis, and in treatment initiation. In our case report, we present a the Flurodeoxyglocose Positron Emission Tomography-Computed Tomography (FDG PET/CT) findings of a patient suffering from malignant amelanotic melanoma and its histopathological confirmation and immunohistochemistry (IHC) correlation In the described case, amelanotic melanoma masqueraded as adenocarcinoma of the rectum in the pathology as well the clinical course. Our case highlights the importance of obtaining a tissue diagnosis and IHC confirmation whenever unusual PET/CT findings are encountered.

Incidental detection of clinically occult follicle stimulating hormone secreting pituitary adenoma on whole body 18-Fluorodeoxyglucose positron emission tomography-computed tomography

A 73-year-old man, known case of Hodgkins lymphoma, underwent 18-Fluorodeoxyglucose positron emission tomography-computed tomography (18-FDG PET-CT) for post-chemotherapy evaluation of the disease status. The scan revealed focal increased FDG uptake in pituitary fossa. The CT images showed homogenously enhancing pituitary lesion causing expansion of the sella. A possibility for the presence of pituitary adenoma was raised in the report. Hormonal assay of the patient showed raised follicle stimulating hormone (FSH) level of 18 IU/ml (normal range for males up to 5 IU/ml). All the other pituitary hormones were within the normal range. Nuclear magnetic resonance (NMR) imaging of brain showed a pituitary lesion with expanded sella pushing the optic chiasma superiorly. NMR findings confirmed the presence of pituitary macroadenoma. A final diagnosis of FSH secreting pituitary macroadenoma was made.

Fluorodeoxyglucose positron emission tomography-computed tomography findings in a case of xanthogranulomatous pyelonephritis

Xanthogranulomatous pyelonephritis (XGNP) is an uncommon condition characterized by chronic suppurative renal inflammation that leads to progressive parenchymal destruction. This condition can clinically present as recurrent urinary tract infections, flank pain, hematuria, and occasionally sepsis, and weight loss. This condition is usually associated with obstructing renal calculus. We present 18-fluorodeoxyglucose positron emission tomography-computed tomography (18-FDG PET/CT) findings in an elderly male suffering from pyrexia and weight loss and suspected urinary tract infection. PET/CT findings in this case lead to diagnosis of XGNP. This diagnosis should be kept in mind while evaluating similar symptoms and PET/CT scan findings.

Somatostatin receptor positron emission tomography/computed tomography (PET/CT) in the evaluation of opsoclonus-myoclonus ataxia syndrome

Opsoclonus-myoclonus ataxia (OMA) syndrome is the most common paraneoplastic neurological syndrome of childhood, associated with occult neuroblastoma in 20%-50% of all cases. OMA is the initial presentation of neuroblastoma in 1%-3% of children. Conventional radiological imaging approaches include chest radiography and abdominal computed tomography (CT). Nuclear medicine techniques, in form of 123I/131I-metaiodobenzylguanidine (MIBG) scintigraphy have been incorporated in various diagnostic algorithms for evaluation of OMA. We describe use of somatostatin receptor PET/CT with 68Gallium- DOTA-DPhe1, Tyr3-octreotate (DOTATATE) in diagnosis of neuroblastoma in two cases of OMA.

Prostatic Adenocarcinoma Masquerading as Generalized lymphadenopathy and Mimicking lymphoma on FDG PET/CT: Diagnosis, Staging, and Evaluation of Therapy Response by FDG PET/CT

We report a case of prostatic adenocarcinoma, initially presenting with generalized lymphadenopathy, and mimicking lymphoma on flurodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT). Our case suggests that in elderly men presenting with generalized lymphadenopathy, the diagnosis of metastatic prostatic carcinoma should not be overlooked even in the absence of typical urinary symptoms.The establishment of a diagnosis of metastatic prostate carcinoma is important, because even widespread prostate cancer may be responsive to hormonal treatment, as demonstrated by this case.We also describe the use of FDG PET/CT to diagnose, stage, and evaluate response to hormonal treatment in a given patient.