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To evaluate the diagnostic role of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) in initial staging and restaging of anorectal melanoma. This was a single-institution, retrospective observational study; patients for initial staging and with clinical or radiological suspicion of disease recurrence referred for PET/CT between January 2006 and December 2015 were included in the study. Diagnostic performance of PET/CT was evaluated for baseline staging and disease recurrence. A total of 61 patients who were referred for initial staging were included. PET/CT correctly detected primary lesion in 57 (93.44%) cases, regional nodes in 46 (75.4%) cases, nonregional nodes in 22 (36%) cases, and distant metastases in 25 (41%) cases. The sensitivity (SN); specificity (SP); positive predictive value (PPV); negative predictive value (NPV); and accuracy for primary lesion, regional nodes, nonregional nodes, and distant metastases were 96.6%, 100%, 100%, 50%, and 96.7%; 97.9%, 100%, 100%, 93.3%, and 98.4%; 100%, 100%, 100%, 100%, and 100%; and 100%, 100%, 100%, 100%, and 100%, respectively. A total of 24 patients were included for suspected recurrence/restaging. All the patients were treated previously by surgery, radiotherapy, or chemotherapy. PET/CT detected disease recurrence in 20 (83.3%) patients. Ten patients had recurrence at the primary site, 8 of whom also had distant metastases and 2 had only locoregional metastatic nodes. In the remaining 10 patients, there was no primary site recurrence; however, 2 patients had locoregional nodal and distant metastases and 8 patients had only distant metastases. PET/CT was false negative in 1 patient, which missed liver metastasis. SN, SP, PPV, and NPV of PET/CT was found to be 95%, 100%, 100%, and 75%, respectively, with accuracy of 96%. PET/CT demonstrates overall high diagnostic accuracy in the initial staging and detection of recurrent disease in cases of anorectal melanoma. [ABSTRACT FROM AUTHOR]

Orbital swelling comprises wide spectrum of pseudotumors, benign and malignant tumor. Malignant tumor may be primary or secondary tumor, and they constitute about 36% of orbital tumors in adult. Fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) scan is extensively used in hematological malignancies and in solid tumors for staging, treatment response, and restaging. Recently, the use of FDG-PET/CT in orbital malignancies has gained importance. The aim of this pictorial essay is to illustrate few important orbital malignancies detected in F-18 FDG-PET/CT and discuss its role in assessing the primary lesion and associated systemic finding. [ABSTRACT FROM AUTHOR]

The aim of the study was to evaluate the diagnostic accuracy of positron emission tomography/computed tomography (PET/CT) in staging patients with primary cutaneous malignant melanoma (CMM). We further compared the performance of PET/CT with conventional imaging (CI) (CT and ultrasonography [USG]) and assessed the impact of PET/CT on disease management. This was a single institution, prospective, double-blinded study, recruiting a total of 70 treatment naïve patients. The sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) of PET/CT for N staging were 86%, 96%, 80%, and 97%, respectively. The sensitivity, specificity, NPV, and PPV of PET/CT for M staging were 87%, 100%, 93%, and 100%, respectively. The diagnostic accuracy of the PET/CT was superior to CI for N staging (90% vs. 84% for CT and 80% for USG) and M staging (95% vs. 90% for CT). No statistically significant difference was noted between PET/CT and CI for N staging (PET/CT vs. CT, P = 0.125; PET/CT vs. USG, P-0.063) or M staging (PET/CT vs. CT, P = 0.125). PET/CT upstaged 23% of patients with clinically localized disease and 58% of patients with clinically palpable regional nodes. To conclude, fluorodeoxyglucose PET/CT is a highly sensitive and specific imaging modality for preoperative staging of primary CMMs. PET/CT impacts disease management in significant number of patients and should be especially recommended in all patients with clinically palpable regional nodes. [ABSTRACT FROM AUTHOR]

To evaluate the accuracy of fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) in staging and restaging of patients with mucosal melanomas (MM) of head and neck. Patients who underwent PET/CT at our institution, with a biopsy proven diagnosis of MM of the head and neck between March 2006 and December 2013 were included in the study. Nineteen patients with MM of the nasal cavity, paranasal sinuses, and oral cavity were included, of which 12 were for staging and seven for restaging. PET/CT had 100% sensitivity (SN), specificity (SP), positive predictive value (PPV), and negative predictive value (NPV) for detection of the primary. SN of 91.7%, SP of 100%, PPV of 100%, and NPV of 87.5% were seen for nodal metastases. For distant metastases, SN of 85.7%, SP of 100%, PPV of 100%, and NPV of 92.3% were noted. The disease was upstaged from loco-regional to metastatic in 32% leading to treatment change in 25% in the staging group and 43% in the restaging group. PET/CT demonstrates good overall accuracy in evaluation of patients with MM of the head and neck. The main strength of PET/CT lies in detection of distant metastatic disease due to extended whole-body field of view. [ABSTRACT FROM AUTHOR]

Perineural spread in HNSCC is associated with dismal prognosis and decreased overall survival. Clinical diagnosis of this relatively asymptomatic entity is usually delayed and made incidentally on imaging. MRI is gold standard imaging for early diagnosing of this condition owing to its excellent anatomic resolution. With the ever increasing use of PET/CT in commonly encountered cancer such as HNSCC for staging and re-staging, observing perineural spread on PET/CT is not infrequent. Through this pictorial essay we demonstrate the common patterns of perineural spread in HNSCC on PET/CT with the aim of improving reporting accuracy across readers. [ABSTRACT FROM AUTHOR]

Introduction: Metronomic chemotherapy (MC) is a novel therapeutic variation for resistant cancers, wherein chemotherapeutic drugs are administrated in low doses with no prolonged drug-free break. It lessens the level of toxicity, is better tolerated and enhances the quality of life. This retrospective analysis was undertaken to evaluate whether anatomical (computed tomography [CT]) or functional (positron emission tomography [PET]) imaging be used for response assessment in patients on MC. Materials and Methods: A total of 16 males and 27 females with age range of 12-83 years on MC who underwent PET/CT were assessed by new response evaluation criteria in solid tumors (RECIST 1.1) and PET response criteria in solid tumors (PERCIST 1.0). Results: Concordance between RECIST 1.1 and PERCIST was seen in 32 (75%) patients. There was discordance in 11 (25%) patients. In patients with discordance, the results were confirmed by follow-up imaging. PET upstaged the disease in 81% of patients (9/11) and down-staged the disease in 19% of patients (2/11). Conclusions: Metabolic response accurately identified the disease status as assessed by clinical or imaging follow-up. Alteration in morphology takes time to manifest, which is demonstrated by CT or magnetic resonance; whereas in MC which brings about tumor dormancy, assessing metabolic response by PET would be more appropriate. MC is usually given in palliative setting but in few cases complete metabolic response was demonstrated in our study. In such a scenario this form of treatment has the potential to become an adjunct mode of treatment in some tumors. This needs to be evaluated with larger, homogenous patient population in a prospective mode. [ABSTRACT FROM AUTHOR]

The seeding of tumor through cerebrospinal fluid (CSF) from primary intracranial tumors is very rare, often goes undetected, and is usually identified only on autopsy. CSF cytology along with magnetic resonance imaging constitutes the standard approach of diagnosing this grave condition. Use of fluoro-2-deoxyglucose positron emission tomography/computed tomography (PET/CT) in indentifying spinal metastases from primary intracranial malignancies is very limited and has been reported in patients with metastatic glioblastoma multiforme and medulloblastomas. We present a rare case of metastatic anaplastic ependymoma to show the potentially clinically utility of PET/CT in diagnosing leptomeningeal or the so-called "drop" metastases. [ABSTRACT FROM AUTHOR]

Osteosarcoma (OS) is the most common nonhematolymphoid primary bone malignancy characterized by osteoid or new bone formation. Lungs and bones are the most common sites of metastases. We report a case where unusual sites of the soft tissue recurrence from OS were detected on restaging fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography scan done post 6 years of disease free interval. [ABSTRACT FROM AUTHOR]

Extraneural (EN) metastases and leptomeningeal (LM) metastases from certain primary central nervous system (CNS) tumors, such as pinealoblastomas, are not very common and mostly detected on autopsy. Clinical detection of this entity is, however, very rare and can be attributed to increasing overall survival or probably increased use of surveillance imaging in patients with brain tumors. We demonstrate through this case the potential adjunctive role of positron emission tomography/computed tomography in the identification of asymptomatic LM/EN metastases in high-risk primary CNS tumors. [ABSTRACT FROM AUTHOR]