Incidence of exclusive extrapelvic skeletal metastasis in prostate carcinoma on bone scintigraphy.

BACKGROUND: Bone is one of the common sites of metastasis from prostate carcinoma. Bone scintigraphy (BS) is one of the most sensitive imaging modalities currently used for bone metastatic work-up. Skeletal metastasis in prostate carcinoma commonly involves pelvic bones but rarely involves extrapelvic-extraspinal sites. AIM: To retrospectively analyze the BS data to determine the pattern of skeletal metastases in the prostate carcinoma. METHODS: This retrospective observational study involves patients with biopsy-proven prostate carcinoma referred for BS for staging assessment. Patients with abnormal BS were evaluated for the pattern of skeletal involvement and data were presented in descriptive format in the form of percentages. RESULTS: A total of 150 patients with biopsy-proven prostate cancer who were referred for staging were included in the study. Thirteen of 150 patients (8.67%) had no abnormal uptake on planar images, ruling out metastatic disease. Twenty-four patients (16%) had heterogeneous uptake in the spine with distribution characteristic of degenerative disease and no scan pattern of metastatic disease. Thirty patients (20%) had multifocal uptake involving both pelvic and extra pelvic bones on planar images typical for skeletal metastasis and were considered metastatic. Eighty-three out of 150 patients (55.3%) had increased tracer uptake, which was indeterminate, thus, single photon emission computed tomography-computed tomography (SPECT-CT) was acquired, which showed 51 with metastatic disease, 31 benign lesions, and one indeterminate finding. Seven of 150 patients had exclusive pelvic bone uptake, which was found to be metastatic in 4/7 patients in SPECT-CT. Fifty six out of 150 patients showed exclusive extrapelvic tracer uptake, of which only 3 had vertebral metastatic disease. None of the patients with increased uptake exclusively in the extrapelvic-extraspinal location was metastatic. CONCLUSION: The incidence of exclusive extrapelvic skeletal metastatic disease in prostate carcinoma is 2% (excluding one patient with indeterminate findings). Further, none of the patients in the current study had exclusive extrapelvic-extraspinal metastasis. Thus, exclusive extrapelvic-extraspinal focal abnormality on planar BS carries a very low probability of metastatic disease and hence, further imaging or SPECT-CT can be safely avoided in such cases.

Adrenal Oncocytoma: A Rare Tumor with Conflicting Imaging Features.

Oncocytic adenomas are rare benign tumors that typically originate in organs such as the kidneys, thyroid, parathyroid, salivary glands, or pituitary gland. Oncocytic adenoma of the adrenal gland is extremely rare. It often shows heterogeneous, nonspecific features on anatomic imaging, as well as high 18F-FDG avidity despite its benign nature. The definitive diagnosis relies on histopathologic examination, including immunohistochemistry. We present an incidentally detected benign adrenal oncocytic adenoma with intense 18F-FDG uptake mimicking sinister pathologies.

Diagnostic Performance of FAPI PET/CT vs. 18F-FDG PET/CT in Evaluation of Liver Tumors: A Systematic Review and Meta-analysis.

Objectives: Primary liver tumors constitute one of the most common tumors. These are aggressive tumors with poor survival. Fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT), most commonly used functional imaging, shows limited tracer retention and poor tumor to background ratios (TBR). Novel 68Ga-fibroblast-activation-protein inhibitor (FAPI) PET/CT has shown better tracer uptake and detection efficacy in liver tumors. However, most of the available literature is limited to single center studies with limited number of patients. So, we tried to review and analyze the head-to-head comparison of 18F-FDG PET/CT and 68Ga-FAPI PET/CT in evaluation of liver tumors. Methods: Literature available on head to head comparison of diagnostic accuracy of 18F-FDG PET/CT and 68Ga-FAPI PET/CT was searched in databases like PubMed, SCOPUS, EMBASE and Google Scholar for published original studies till April 2023. The relevant studies were selected and assessed using the Revised Tool for the Quality Assessment of Diagnostic Accuracy Studies-2 checklist. A random-effect model was used for calculating pooled sensitivity and specificity. They were represented with 95% confidence intervals (95% CI) and demonstrated in Forest plots. I-square statistic was used to assess heterogeneity in the studies. Results: Pooled sensitivity and specificity of FAPI PET/CT and 18F-FDG PET/CT for detection of primary liver tumors was 94.3% (95% CI: 90.6-96.8%); 89.3% (95% CI: 71.8-97.7%) and 56.1% (95% CI: 49.7-62.5%); 96.4% (95% CI: 81.7-99.9%) respectively. Pooled sensitivity for detection of extrahepatic metastatic disease was 92.2% (range: 88.1-100%; 95% CI: 87.8-95.4%) and 72.4% (range: 69.8-76.5; 95% CI: 65.9-78.2%) respectively. Also, the maximum standardized uptake value (SUVmax) and TBR were higher for FAPI PET/CT than 18F-FDG PET/CT in the included studies. Conclusion: Overall, FAPI PET/CT showed higher sensitivity for detection of liver tumors with better SUVmax and TBR than 18F-FDG PET/CT.

Rare Case of Primary Leiomyosarcoma of Bone - Findings on 18F-fluorodeoxyglucose Positron Emission Tomography/Computed Tomography.

Primary leiomyosarcoma of bone (PLB) is a rare tumor, constituting <0.7% of all primary bone malignancies. It is clinically aggressive with heterogeneous presentation and a dismal prognosis. The most common presentation is pain with swelling and pathological fracture at times. Limited literature is available on PLB and only about 150 cases have been reported to date with only a few case reports defining the utility of 18F-fluorodeoxyglucose (18-F FDG) positron emission tomography/computed tomography (PET-CT) in its management. We hereby present a case of primary leiomyosarcoma of the right distal femur and the role of FDG-PET-CT in its management.

Role of PSMA-targeted PET-CT in renal cell carcinoma: a systematic review and meta-analysis.

Fluoro-deoxy glucose positron emission tomography/computed tomography (PET/CT), the workhorse of nuclear medicine, has limited utility for renal cell carcinoma (RCC), particularly clear cell variant. Thus, various other tracers have been tried for evaluation of RCC. One of the most promising targets for radiotracers is prostate-specific membrane antigen (PSMA) expressed in abundance in carcinoma-associated neo-vasculature. Thus, we tried to review and analyse the role of PSMA-targeted PET/CT in evaluation of RCC. Databases like PubMed, EMBASE and SCOPUS were searched for original studies published on PSMA-targeted PET/CT in RCC till 30 September 2023. Revised Tool for the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) checklist was used to assess the included studies. Pooled sensitivity and specificity were calculated and represented with 95% confidence intervals (95%CI). Heterogeneity in the studies was assessed by I-square index. Pooled sensitivity and specificity of PSMA-targeted PET/CT for detection of local disease estimates were 87.2% (95%CI: 77-94%) and 100% (95%CI: 92.9-100%), respectively. Pooled sensitivity and specificity for detection of local recurrent disease are 100% (95%CI: 71.5-100%) and 100% (95%CI: 89.4-100%), respectively. Pooled sensitivity and specificity for detection of metastatic disease are 92% (95%CI: 86.2-96%) and 96.9% (95%CI: 83.8-99.9%), respectively. Pooled sensitivity of PSMA-targeted PET/CT for detection of clear cell renal cell carcinoma (ccRCC) and non-ccRCC are 94.7% (95%CI: 88-98.3%) and 75% (95%CI: 35-96.8%), respectively. PSMA-targeted PET-CT demonstrated better diagnostic efficacy for the detection of recurrent RCC. Whilst for staging RCC, it had higher specificity but lower sensitivity. Thus, it can serve as a non-invasive adjuvant tool to conventional imaging in the evaluation of staging of RCC, particularly clear cell variant.

Incidental Detection of Myocardial Ischemia on Whole-Body PET/CT in a Patient With Carcinoma Lung.

ABSTRACT: 18 F-FDG PET/CT being a whole-body technique can detect multiple other critical nononcological findings. Various cardiac disorders identified incidentally on 18 F-FDG have been reported to help in timely management and improve overall patient care. We hereby present one such case where 18 F-FDG PET/CT performed for a workup of carcinoma lung revealed abnormal myocardial FDG uptake in the anteroseptal and apical region, which raised suspicion of myocardial ischemia such as hot spot imaging. On coronary angiography, coronary artery disease was detected and subsequently managed.

False-Positive Radioiodine Uptake in the Cervix in a Patient with Thyroid Cancer.

Radioactive iodine (RAI) accumulation is commonly used for the detection of metastatic disease posttotal thyroidectomy. However, false-positive results have been reported due to abnormal RAI accumulation in some benign pathologies apart from metastatic sites. Here, we present one such case where false-positive I-131 uptake in the pelvis which localized to the cervix and was attributed to menstruation.

Delayed Recurrence of Gall Bladder Cancer as Port-site Metastases with Occult Primary Detected on Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography: A Tale of Two Cases.

Laparoscopic cholecystectomy is a fairly common procedure and is currently considered the gold standard for cholecystectomy. However, the laparoscopic procedure in the presence of gall bladder cancer (GBC) is associated with the risk of port-site metastasis (PSM). Furthermore, in few cases, GBC remains occult even on postoperative histopathology and presents with PSM remotely. Here, we describe two such cases of GBC with occult primary who presented with PSM and also defined the role of fluorine-18 fluorodeoxyglucose positron emission tomography-computed tomography in the management of such cases.

Uterine Metastasis Presenting as Abnormal Uterine Bleeding in a Case of Primary Breast Cancer Identified on 18F-FDG PET/CT.

Metastases to the female genital tract are rare, especially from extragenital primaries. The most common extragenital sites associated with genital metastasis are the gastrointestinal tract (37.6%) followed by the breast (34.9%). It is crucial to differentiate primary from metastatic involvement of the uterus for appropriate patient management. We present one such case of endometrial metastasis in a patient who presented clinically with abnormal uterine bleeding and was diagnosed with primary breast cancer via 18F-FDG PET/CT.

Role of Sentinel Lymph Node Drainage Mapping for Localization of Contralateral Lymph Node Metastasis in Locally Advanced Oral Squamous Cell Carcinoma - A Prospective Pilot Study.

Aim/Background: Sentinel lymph node biopsy (SLNB) has become the standard of care for nodal staging in early-stage oral squamous cell carcinoma (OSCC) as an alternative to elective neck dissection. However, the role of sentinel lymph node (SLN) and lymphatic drainage mapping with image-guided surgery has not been studied in locally advanced OSCC. Therefore, this study was undertaken to evaluate the role of lymphatic drainage mapping in the identification of contralateral cervical lymph node metastasis in locally advanced OSCC (Stage III-IVb). Materials and Methods: We have prospectively analyzed treatment-naïve patients of locally advanced, lateralized OSCC (n = 20). All patients underwent SLN imaging using peritumoral injection 0.5-1.0 mCi of 99 mTc-Sulfur colloid (Filtered) and intraoperative identification of contralateral neck nodes using a handheld gamma probe (Crystal Photonics). Results: A total of 20 patients (18 males and 2 females) with a median age of 52.5 (33-70 years) were included. Ipsilateral SLN was localized in 18 (90%) patients. Bilateral cervical nodes were visualized only in 7 (35%) patients on lymphoscintigraphy (LSG). Out of the seven patients, 5 patients underwent bilateral neck dissection and 2 patients had unilateral neck dissection with LSG-guided exploration of contralateral cervical node and intraoperative frozen section examination. Six out of these seven patients had one or other risk factor for contralateral metastasis (patients had either primary in the tongue, involvement of floor of mouth, or tumor thickness >3.75 mm). On postoperative HPE, only 1/20 (5%) patient showed metastasis in the contralateral cervical lymph node. Conclusion: Correct identification of metastatic disease in contralateral neck directly influences clinical management, as it can reduce contralateral neck failure rate and limit the morbidity associated with unnecessary contralateral neck dissection, and it is also crucial in radiotherapy planning in locally advanced OSCC. In the current study, lymphatic drainage mapping showed a metastatic rate of 5% in the contralateral neck nodes in locally advanced, lateralized OSCC. However, the role of SLNB and lymphatic drainage mapping in this subgroup of OSCC needs to be studied in larger population to validate these findings.

Rare Case of Phyllodes Tumor of Breast with Cardiac and Pancreatic Metastases: Findings on 18F-FDG PET/CT.

Phyllodes tumor (PT) represents a rare type of breast tumor arising from the stromal component rather than the epithelium. Metastatic spread occurs hematogenously, with lung, bone, brain, and liver being the most common sites. We present the 18F-FDG PET/CT scan of one such case of phyllodes tumor showing cardiac and pancreatic metastases, which are an extremely rare occurrence.

Lymphoscintigraphy in idiopathic recurrent chylopericardium.

Chylopericardium is a clinical condition due to the accumulation of triglyceride-rich chylous fluid within the pericardial space. It may be primary (idiopathic), without any apparent cause or secondary to some precipitating factors, such as cardiac surgery, malignancy, trauma, infection and radiation. Primary chylopericardium is rare and a diagnosis of exclusion, so far less than 150 cases have been reported in the literature. The authors present a case of recurrent primary chylopericardium diagnosed by lymphoscintigraphy.

Aberrant Radioactive Iodine Uptake in Simple Ovarian Cyst: A Rare Finding.

I-131 whole body scan and therapy play an important role in the follow-up of differentiated thyroid carcinoma patients for the detection of residual thyroid tissue and metastatic disease. However, various false-positive findings have been reported in the literature which can appear as metastases. Here, we present one such case, in which an I-131 posttherapy scan revealed false-positive radioactive iodine uptake which localized to a simple ovarian cyst.

The Vital Role of 131 I-MIBG in Localization of Paraganglioma at Unusual Sites.

Paragangliomas (PGLs) are extra-adrenal neuroendocrine tumors. PGL of the urinary bladder are very rare and commonly present with features of hypertensive crisis, headache, syncope, and other symptoms of sympathetic excess. A few of these tumors are silent at the presentation. Here, we report a case of a urinary bladder PGL, presenting with lower abdominal pain.

Dual thyroid ectopia: A pictorial case series and review of literature.

Ectopic thyroid (ET) is a developmental anomaly of the thyroid gland with the presence of thyroid tissue at sites other than the normal cervical location anterior to second and third tracheal ring due to abnormal migration of the gland. It may be found along the path of descent of the developing thyroid primordium from the foramen caecum to the isthmus of the thyroid and up to the base of the diaphragm. Dual thyroid ectopia, where ET tissue is simultaneously present at two different abnormal locations, is a very rare developmental defect. Only a few cases have been reported worldwide. ET is predominantly seen in females and during puberty when the hormonal demand is high. Patients with ET may remain asymptomatic or present with swelling in the neck, symptoms such as dysphagia, dysphonia, dyspnea, and features of hypothyroidism. The diagnosis is usually made on clinical examination, laboratory tests, imaging studies, and cytology. Careful clinical evaluation is essential as ET may be the only functioning thyroid tissue. Thyroid scintigraphy is an important imaging tool and the gold standard for the diagnosis of ET tissue, as it has high sensitivity and specificity. Early and accurate diagnosis of ET is essential to start hormone replacement and avoid unnecessary surgery. The authors report here a series of four patients with dual ET tissue, diagnosed on thyroid scintigraphy.