Extracranial Meningioma-Pelvic Bone on FDG PET/CT: A Rare of the Rarest Site.

ABSTRACT: Meningiomas are benign extra-axial tumors of the central nervous system. Extracranial meningiomas are extremely rare (2%) and can develop as a direct extension from a primary intracranial meningioma or as a true primary extracranial meningioma originating from ectopic arachnoid cells. We report an extremely unusual case of a 61-year-old woman who was diagnosed with pelvic meningioma with the help of PET/CT and PET/CT-guided biopsy. The clinicopathological features of the patient and immunoprofile of the tumor are presented.

PSMA Avidity in the Heterotropic Ossification-An Incidental Finding on PSMA PET/CT.

ABSTRACT: The upregulations of prostate-specific membrane antigen (PSMA) antigen are used for the presence of prostate cancer. However, published literature shows incidentally detected PSMA uptake in various nonprostatic benign and malignant conditions, which led to questioning the specificity of PSMA-targeted PET. In present case, we highlighted the abnormal PSMA expression in the benign bone abnormality.

FDG PET-CT in Clinical Management of a Rare Case of Primary Hepatic Lymphoma: Role and Challenges.

The common differential diagnoses for multiple space-occupying hepatic lesions (SOL) are metastases, multifocal hepatocellular carcinoma, and abscess. Primary hepatic lymphomas are rare entities that present many challenges with regard to their management. Fluorodeoxyglucose positron emission tomography-computed tomography is extensively used for the staging and response assessment of lymphomas but it can be challenging and difficult to interpret in cases with isolated liver involvement. We hereby present the case of an 82-year-old lady who presented with multiple liver SOL.

Should fluorodeoxyglucose positron emission tomography/computed tomography be the first-line imaging investigation for restaging the laryngeal carcinoma patients?

Posttreatment detection of residual/recurrence disease in the head and neck cancers is not an easy task. Treatment induces changes create difficulties in diagnosis on conventional imaging (computed tomography [CT], magnetic resonance imaging) as well as macroscopic inspection (direct laryngoscopy). Hence, we evaluate the diagnostic performance of contract-enhanced F-18 fluorodeoxyglucose positron emission tomography (FDG PET)/CT in restaging of laryngeal carcinoma Postchemotherapy-surgery and/or radiation therapy. We retrospectively analyzed patients of carcinoma larynx (n = 100) who has completed treatment and were referred for FDG PET/CT. Two reviewers performed image analysis to determine recurrence at primary site and/lymph nodes and distant metastases. Receiver operating characteristic (ROC) was used to determine the maximum standardized uptake value (SUVmax) cut off for disease detection. Histopathological examination and clinical or imaging follow-up were taken as gold standard for recurrence. One hundred laryngeal carcinoma patients with mean age of 57.2 years (range of 40-76) were included in the present study. Among the 100 patients, 96 were male and remaining 4 were female. The average interval between completion of treatment and FDG PET/CT scan was 8.5 months (minimum 6 months). Of the 100 patients, FDG PET/CT detected FDG avid lesions in 66 patients. Sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of FDG PET/CT for residual/recurrence disease detection was 90.3%, 73.7%, 84.8%, 82.3%, and 84.0%, respectively (P < 0.05). In addition, in 10 patients, metachronous primaries were detected (lung-4, thyroid-2, tongue, colon, esophagus, and lymphoma-one each). On ROC curve analysis, SUVmax >6.1 had sensitivity and specificity of 80.6% and 94.7% respectively for detection of recurrent/metastatic disease. FDG PET/CT demonstrates high diagnostic accuracy for detection of residual/recurrent disease in treated laryngeal cancer patients and our findings suggest that this imaging modality should be the first-line diagnostic investigation in this cohort of patients.

Follicular Thyroid Carcinoma with Unusual Radioiodine-Refractory Breast Metastasis Mimicking Primary Breast Malignancy.

The breast is an unusual site for metastasis from malignant tumors, although it may be the first manifestation of an extramammary primary malignancy typically arising in the lung, skin (melanoma), ovary, or lymph nodes (lymphoma). Breast metastasis from thyroid carcinoma is extremely rare and may take years to develop, as differentiated thyroid carcinoma is usually indolent and slow-growing and metastasizes to the lymph nodes, lungs, and bones. Here, we present the case of a middle-aged woman (after subtotal thyroidectomy for multinodular goiter 24 y previously) showing discordant 18F-FDG and iodine avidity in proven metastatic disease involving the lymph nodes, bones, spleen, and breast on whole-body 131I and 18F-FDG scans due to tumor heterogeneity.

Is F-18 FDG PET/computed tomography a useful tool to restage the patients with tongue carcinoma?

OBJECTIVE: The aim of this study was to evaluate the diagnostic performance of contrast-enhanced F-18 fluoro-2-deoxyglucose (F-18 FDG) PET/computed tomography (CT) in restaging of tongue carcinoma. MATERIAL AND METHODS: Retrospectively analysis of carcinoma tongue patients (n = 110) who were treated and referred for FDG PET/CT. Histopathological examination and clinical or imaging follow-up were taken as gold standard. RESULTS: Of 110 patients, FDG PET/CT detected FDG avid lesions in 69 (62.7%) patients. Sensitivity, specificity and diagnostic accuracy of FDG PET/CT were 92.9%, 90.0% and 91.8%, respectively, for residual/recurrence disease detection (P < 0.05). Additionally, in six patients, metachronous primaries were also detected [lung (4), esophagus and lymphoma (1) each]. The mean maximum standardized uptake value (SUVmax) with 95% confidence interval for primary site recurrence, regional lymph nodes and metastatic lesions was 11.51 (9.53-13.48), 69 (62.7%) (7.88-11.48) and 8.94 (3.11-14.76), respectively. CONCLUSION: FDG PET/CT demonstrates high diagnostic accuracy for detection of residual/recurrent disease in treated tongue cancer patients and PET/CT should be considered as first-line diagnostic investigation in these patients.

Isolated Malignant Portal Vein Thrombus in Colon Carcinoma: A Rare Finding on 18F-FDG PET/CECT.

In the absence of hepatic metastasis in abdominal cancers, an isolated malignant portal vein thrombus is very rare. The presence of a malignant thrombus has clinical significance for determining the stage, treatment, and prognosis. 18F-FDG PET/CECT is a noninvasive modality for discriminating between malignant and benign thrombi. We present a case of primary sigmoid colon carcinoma for which 18F-FDG PET/CT showed, in addition to the 18F-FDG-avid primary lesion, an 18F-FDG-avid filling defect in the portal vein, likely malignant thrombus.

Real Time F-18 FDG PET-CT-Guided Metabolic Biopsy Targeting Differential FDG Avidity in a Pulmonary Blastoma.

Pulmonary blastoma (PB) is a rare thoracic malignancy and preoperative diagnosis is challenging. A young man presented with dyspnea and chest pain for 3-4 months and chest-computed tomography (CT) revealed large mass in the left lung upper lobe and pleural effusion. Repeated CT-guided fine-needle aspiration cytology from the lesion and pleural fluid aspiration was negative for malignancy. F-18-fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET-CT) revealed heterogeneous tracer avidity in left lung mass with areas of necrosis. Real-time PET-CT-guided biopsy from metabolically active component of the lesion revealed biphasic PB on histopathology.

Tuberculosis Presenting as Cutaneous Erythema Nodosum on 18F-FDG PET/CT.

The present article presented a 47-year-old woman with areas of nodular swelling and discoloration involving bilateral lower limbs since 12 months. Biopsy from skin lesions revealed erythema nodosum. As erythema nodosum can be secondary to multiple etiologies, whole-body F-FDG PET/CT was performed to assess the disease distribution and guide the site of biopsy. F-FDG PET/CT revealed metabolically active mediastinal lymphadenopathy in addition to the skin lesions. Endobronchial ultrasound-guided biopsy from subcarinal lymph node revealed tuberculosis.

Orbital Metastasis: Rare Initial Presentation of an Occult Gall Bladder Carcinoma.

Orbital metastases are known to arise from primary breast carcinoma followed by prostate, malignant melanoma, and lung carcinoma. We report a case of orbital metastasis as the initial presentation of an occult primary gall bladder carcinoma. The FDG PET/CT helped in localizing the occult distant primary site, which previously escaped detection, and also enabled the evaluation of orbital metastasis.

A rare adult renal neuroblastoma better imaged by 18F-FDG than by 68Ga-dotanoc in the PET/CT scan.

Primary renal neuroblastoma is an uncommon tumor in children and extremely rare in adults. We present a case of a middle aged female having a large retroperitoneal mass involving the right kidney with features of neuroblastoma on pre-operative histopathology. Whole-body fluorine-18-fluoro-deoxyglucose positron emission tomography (18F-FDG PET/CT) and 68Ga-dotanoc PET/CT scans performed for staging and therapeutic potential revealed a tracer avid mass replacing the right kidney and also pelvic lymph nodes. The 18F-FDG PET/CT scan showed better both the primary lesion and the metastases in the pelvic lymph nodes than the 68Ga-dotanoc scan supporting diagnosis and treatment planning.

18F-FDG PET/CT Imaging in Adrenal Cryptococcosis.

Cryptococcosis is a fungal infection, relatively rare in the absence of impaired immunity. Lung or brain may be involved. Cryptococcal dissemination is rare in absence of impaired immunity, and documentation of alone adrenal involvement without central nervous system involvement is rare. Here, we present a case of an immunocompetent patient presented with bilateral adrenal cryptococcosis with adrenal insufficiency, without central nervous system involvement and F-FDG PET/CT correctly identified the residual disease.

68Ga-PSMA Expression in Pseudoangiomatous Stromal Hyperplasia of the Breast.

Ga-labeled prostate-specific membrane antigen ligand PET-CT has emerged as a promising technique to evaluate the extent of disease in patients with prostate carcinoma. We are reporting a 63-year-old man with prostatic carcinoma subjected to Ga-prostate-specific membrane antigen ligand PET-CT for initial staging. In addition to the radiotracer uptake in known primary site (prostate), focal increased radiotracer uptake was also noticed in the left breast. Subsequent biopsy of the breast lesion revealed PASH (pseudoangiomatous stromal hyperplasia), which is a benign mesenchymal proliferative lesion that may present clinically as palpable mass requiring further evaluation to rule out malignancy.

Disseminated Skeletal Muscle and Cardiac Metastasis from Squamous Cell Carcinoma of the Lung Detected with FDG and FLT PET/CT.

Lung cancer is one of the leading cancers all over the world. Positron emission tomography (PET) using 18F fluorodeoxyglucose (18F FDG) is useful for staging of the disease and decide the appropriate management. 3'-deoxy-3'-18 F-fluorothymidine (18F FLT) is a tracer being extensively evaluated currently and is said to represent tumor proliferation. Common sites of metastases from lung cancer include adrenal glands, bone, and brain. Muscle metastasis and cardiac metastasis are uncommon findings. We report a case of squamous cell carcinoma of the lung with metastases to multiple skeletal muscles and myocardium detected with both FDG and FLT PET/computed tomography (CT).

Unusual Presentation of Bladder Paraganglioma: Comparison of (131)I MIBG SPECT/CT and (68)Ga DOTANOC PET/CT.

Extraadrenal chromaffin cell-related tumors or paragangliomas are rare, especially in the bladder, accounting for less than 1% of cases. We report a 16-year-old boy who presented with hematuria and paroxysmal headache and was found to have a prostatic growth infiltrating the urinary bladder on anatomical imaging. Iodine-131 ((131)I) metaiodobenzylguanidine (MIBG) whole-body scanning and subsequently gallium-68 ((68)Ga) DOTANOC positron emission tomography/computed tomography (PET/CT) were performed. The MIBG scan revealed a non-tracer-avid soft-tissue mass, while DOTANOC PET/CT revealed a tracer-avid primary soft-tissue mass involving the urinary bladder and prostate with metastasis to the iliac lymph nodes. He underwent surgical management; histopathology of the surgical specimen revealed a bladder paraganglioma, whereas the prostate was found to be free of tumor.

Malignant Jugular Paraganglioma: Unusual Presentation on 68Ga DOTANOC PET/CT.

Metastatic jugular paraganglioma are rare tumors and account for less than 1% of the cases of head and neck tumors. We report a 40-year-old woman of jugular paraganglioma, presenting with right-sided neck swelling, hearing loss, and pulsatile tinnitus. Contrast-enhanced CT temporal bone revealed a mass in the right jugular foramina and extending inferiorly to internal jugular vein. Ga DOTANOC PET/CT was performed, which revealed somatostatin receptor expressing lesion in the right internal jugular vein and extension into sigmoid sinus and additional metastatic focus in the sacrum.

Dual thyroid ectopia-role of thyroid scintigraphy and neck ultrasonography.

Ectopic thyroid tissue (ETT) is a rare developmental anomaly of the thyroid tissue where the thyroid gland is not located in its usual position. Dual thyroid ectopia is far rarer. This case of a 5-year-old euthyroid girl with thyroglossal cyst was planned for surgery. Presurgical ultrasonography (USG) of the neck followed by thyroid scintigraphy was performed. There was absent normal thyroid gland with single ETT in neck swelling on USG. However, thyroid scintigraphy revealed two ectopic foci of thyroid tissue; one was corresponding to neck swelling, and other was superior to it at the base of the tongue along with absent eutopic thyroid gland. The repeat neck USG could demonstrate the same. The present case emphasizes that, if the thyroid gland is not visible by USG; ETT should be evaluated with thyroid scintigraphy in case of thyroid dysgenesis.