Abdominopelvic Hemangiopericytoma Mimicking Neuroendocrine Tumor on 68 Ga-DOTANOC PET/CT.

ABSTRACT: We present the case of a 60-year-old man who was being evaluated for 2 intra-abdominal masses. The masses were tracer avid on 68 Ga-DOTANOC PET/CT and were suggestive of neuroendocrine tumor. Histopathology, however, confirmed the masses to be hemangiopericytoma. Hemangiopericytoma comes under the umbrella of solitary fibrous tumors, a rare tumor group arising from the mesenchymal cells. Solitary fibrous tumors commonly arise from the pleura but can occur anywhere in the body. Intra-abdominal hemangiopericytoma are extremely rare and should be kept in mind as one of the differential diagnoses for 68 Ga-DOTA peptide-avid tumors.

Askin's Tumor a Rare Clinical Entity of Thoracopulmonary Region Cresenting as a Case of Paraparesis: Findings on 18F-FDG PET/CT.

Askin's tumors are rare malignant neoplasms located in the thoracopulmonary region and mainly occur in children and adolescents. In this report, we describe a case of histologically proven Askin's tumor in a 24-year-old male. The patient was admitted with a history of 3-month lower back pain and with a rare presentation of paraparesis.

A Rare Case of Solitary Fibrous Tumor of Maxilla: Findings on F-18 FDG and Ga-68 DOTANOC PET-CT.

Solitary fibrous tumor (SFT) is a rare tumor of mesenchymal origin that most commonly involves the pleura but can be found anywhere in the body. SFT can range from indolent benign tumors to aggressive malignant tumors, and pre-operative diagnosis is based mainly on imaging. In this case report, we describe an extremely rare case of SFT of left maxilla on F-18 FDG PET-CT and Ga-68 DOTANOC PET-CT. Very few cases of PET-CT findings in SFT are reported in literature; and to our knowledge, none involving the maxilla. By highlighting the findings on F-18 FDG and GA-68 DOTANOC PET-CT, we aim to further add on to the role of both the tracers in the diagnosis and management of this tumor group.

Malignancy-Associated Sarcoid-Like Reaction in a Case of Triple-Negative Breast Cancer on F-18 Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography.

We describe the case of a 54-year-old woman with triple-negative breast cancer whose baseline F-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) showed hypermetabolic left breast primary, ipsilateral axillary lymphadenopathy, lung nodules, and mediastinal lymph nodes. Histopathological examination of tissue from mediastinal lymph nodes confirmed a diagnosis of sarcoid-like reaction. Chemotherapy may induce or cause a flare-up of malignancy-associated sarcoid-like reaction. However, in our patient's post-chemotherapy F-18 FDG PET/CT, there was reduction in size and uptake of the mediastinal lymph nodes along with partial response shown by the other lesions. We aim to describe this rare course of malignancy-associated sarcoid-like reaction and highlight the role of F-18 FDG PET-CT in such cases.

Askin Tumor - Presenting as a Case of Paraparesis: A Rare Clinical Entity. Case Report and Findings on 18F-Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography.

Askin tumors are rare malignant neoplasms located in the thoracopulmonary region and mainly occur in children and adolescents. In this report, we describe a case of histologically proven Askin's tumor in a 24-year-old male. The patient was admitted with a history of 3-month lower back pain and with a rare presentation of paraparesis.

Extensive Metastatic Vascular Calcification in a Patient with Chronic Renal Failure and Tubercular Osteomyelitis as Seen on F-18 Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography.

A 48-year-old male with known tubercular osteomyelitis of the left elbow and chronic renal failure presented with PTH independent hypercalcemia and underwent F-18 fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) to look for any underlying malignancy that might be causing his hypercalcemia. The PET/CT did not reveal any malignancy, but extensive metastatic calcification of small- and medium-sized arteries was noted throughout the body with relative sparing of large vessels. Alkaline tissue such as lungs, gastric mucosa, and kidneys that are usually involved in metastatic calcification were also spared. The underlying pathology for this kind of metastatic calcification was most likely chronic granulomatous disease, which was tubercular osteomyelitis in this patient. We present the PET/CT scan images of this unusual case of metastatic vascular calcification.

Re-challenge of immune checkpoint inhibitor pembrolizumab with concurrent tocilizumab after prior grade 3 pneumonitis.

Immune checkpoint inhibitors (ICIs) are associated with specific immune-related adverse events (irAEs) which are unique compared to cytotoxic chemotherapy. For life-threatening adverse events including grade 3 or more, permanent discontinuation of the ICIs is recommended, albeit without much robust evidence. Safe re-challenge of ICIs with concurrent immunosuppression has been reported with irAEs like gastrointestinal toxicity and arthritis. Here we present a case of a lady with undifferentiated pleomorphic sarcoma with programmed death ligand1 expression, who showed a complete response to pembrolizumab used as third-line therapy. However, it had to be stopped after 22 doses when the patient developed grade 3 pneumonitis. In view of progression off pembrolizumab, and lack of other effective alternatives, pembrolizumab was re-challenged with concurrent interleukin-6 (IL-6) blockade using tocilizumab. This was based on preliminary evidence on the role of IL-6 in mediating the irAEs, especially pneumonitis. The patient re-attained a complete response with pembrolizumab. There was no recurrence of the pneumonitis after rechallenging, and there was partial radiographic resolution of the ICI-interstitial lung disease after the combination therapy.

Langerhans Cell Histiocytosis of Bilateral Parotid and Submandibular Glands: Findings on 18F-FDG PET/CT.

ABSTRACT: Langerhans cell histiocytosis is a disorder of the mononuclear phagocytic system. Virtually any organ can be involved, the bone, skin, lungs, and pituitary gland being the most common. We describe the case of a 30-year-old man who presented with painless neck swelling. 18 F-FDG PET/CT showed bilateral bulky parotid and submandibular glands with increased metabolic activity. Histopathology confirmed the diagnosis of Langerhans cell histiocytosis. To our knowledge, there has been no description of 18 F-FDG PET/CT findings in Langerhans cell histiocytosis of salivary glands in literature. We aim to aid in the diagnosis and management of this rare presentation.

Lincoln Sign in a Case of Primary Hyperparathyroidism on 18 F-Fluorocholine PET/CT.

ABSTRACT: Lincoln sign or black beard sign is one of the signs that have been classically described on bone scintigraphy in monostotic Paget disease, when mandible is involved. Extensive involvement of the mandible causes increased radiotracer uptake from one mandibular condyle to the other, resembling a black beard. We present the case of a 14-year-old girl with primary hyperparathyroidism who underwent an 18 F-fluorocholine PE/CT to locate the parathyroid adenoma. MIP image of the PET/CT incidentally showed black beard sign due to increased radiotracer uptake in the mandible.

Gastric Mucosal Viability Assessment Using 99mTcO4 in a Case of Pure Esophageal Atresia After Isoperistaltic Gastric Tube Replacement.

ABSTRACT: Gastric surface mucosal cells are responsible for the uptake and secretion of 99mTcO4, a feature that has been used in imaging heterotopic gastric mucosa. We used the same principle to look for gastric mucosal viability in this case of pure esophageal atresia admitted for cervical stomal closure after a previous isoperistaltic gastric tube (IGT) replacement procedure. 99mTcO4 scintigraphy was done after encountering a failure to maneuver the esophagoscope through the IGT. The study was helpful in assessing the loss of gastric mucosal viability in an intervening segment of the IGT.

Adipocyte-derived extracellular vesicles increase insulin secretion through transport of insulinotropic protein cargo.

Adipocyte-derived extracellular vesicles (AdEVs) are membranous nanoparticles that convey communication from adipose tissue to other organs. Here, to delineate their role as messengers with glucoregulatory nature, we paired fluorescence AdEV-tracing and SILAC-labeling with (phospho)proteomics, and revealed that AdEVs transfer functional insulinotropic protein cargo into pancreatic ß-cells. Upon transfer, AdEV proteins were subjects for phosphorylation, augmented insulinotropic GPCR/cAMP/PKA signaling by increasing total protein abundances and phosphosite dynamics, and ultimately enhanced 1st-phase glucose-stimulated insulin secretion (GSIS) in murine islets. Notably, insulinotropic effects were restricted to AdEVs isolated from obese and insulin resistant, but not lean mice, which was consistent with differential protein loads and AdEV luminal morphologies. Likewise, in vivo pre-treatment with AdEVs from obese but not lean mice amplified insulin secretion and glucose tolerance in mice. This data suggests that secreted AdEVs can inform pancreatic ß-cells about insulin resistance in adipose tissue in order to amplify GSIS in times of increased insulin demand.

Glucose-dependent insulinotropic polypeptide regulates body weight and food intake via GABAergic neurons in mice.

The development of single-molecule co-agonists for the glucagon-like peptide-1 (GLP-1) receptor (GLP-1R) and glucose-dependent insulinotropic polypeptide (GIP) receptor (GIPR) is considered a breakthrough in the treatment of obesity and type 2 diabetes. But although GIPR-GLP-1R co-agonism decreases body weight with superior efficacy relative to GLP-1R agonism alone in preclinical1-3 and clinical studies4,5, the role of GIP in regulating energy metabolism remains enigmatic. Increasing evidence suggests that long-acting GIPR agonists act in the brain to decrease body weight through the inhibition of food intake3,6-8; however, the mechanisms and neuronal populations through which GIP affects metabolism remain to be identified. Here, we report that long-acting GIPR agonists and GIPR-GLP-1R co-agonists decrease body weight and food intake via inhibitory GABAergic neurons. We show that acyl-GIP decreases body weight and food intake in male diet-induced obese wild-type mice, but not in mice with deletion of Gipr in Vgat(also known as Slc32a1)-expressing GABAergic neurons (Vgat-Gipr knockout). Whereas the GIPR-GLP-1R co-agonist MAR709 leads, in male diet-induced obese wild-type mice, to greater weight loss and further inhibition of food intake relative to a pharmacokinetically matched acyl-GLP-1 control, this superiority over GLP-1 vanishes in Vgat-Gipr knockout mice. Our data demonstrate that long-acting GIPR agonists crucially depend on GIPR signaling in inhibitory GABAergic neurons to decrease body weight and food intake.

D actylogyrus kolodynensis sp. n. (Platyhelminthes: Monogenea) infecting gills of Osteobrama cotio (Hamilton, 1822) (Cypriniformes: Cyprinidae) from India.

Dactylogyrus kolodynensis, a new monogenean parasite species, is described from Osteobrama cotio (Cyprinidae) collected from Lawngtlai (Mizoram) and Lucknow (Uttar Pradesh), India, using morphological examination and sequencing of partial 28S rRNA gene. The new species is morphologically characterized and distinguished from closely related congeners by a combination of the following characters: copulatory tube a loose coil of one complete clockwise ring, jaw-shaped accessory piece comprising variable sheathes enclosing and guiding the copulatory tube, and sclerotized vaginal tube, with a terminal flower-bud-shaped vaginal pore. The molecular analyses of specimens of D. kolodynensis collected from two different localities using 28S rRNA gene showed identical genotype that did not match any of the known sequences in GenBank, confirming our initial morphological identification. Dactylogyrus cotius, a sympatric species on the gills of O. cotio, is regarded as a species inquirenda because of its poor description. This is the first report of a monogenean species from Mizoram, in northeast India, bringing the total number of Dactylogyrus species in India to 57.

Antibiotic scintigraphy in tuberculosis: A new horizon?

Tuberculosis (TB) continues to be a major cause of death worldwide that can be effectively treated with timely diagnosis and treatment. With the advent of nuclear imaging techniques like 18Fluorine Fluoro-2-Deoxy-D-Glucose Positron Emission Tomography (18F-FDG) PET/CT, the diagnosis of tuberculosis, particularly its extrapulmonary forms, has received great impetus in cases where microbiological confirmation cannot be achieved. Although detection of mycobacteria either by staining, culture or nucleic acid amplification techniques still form the gold standard of diagnosis, newer diagnostic techniques are always welcome in the field which can expedite clinical management. Use of radiolabeled antibiotics is one such evolving sphere which needs further research. Moving ahead from radiolabeled leukocytes, antibiotics are being increasingly focused upon to act as a vehicle to locate infectious lesions. Antibiotics like ciprofloxacin have been labeled with diagnostic radionuclides such as Technetium-99m (Tc-99m) and used to image many infectious diseases with encouraging results in TB. However, the nonspecific attributes of ciprofloxacin have hindered its growth to assist the diagnosis of TB. A novel approach would be to utilize ethambutol, a specific antitubercular agent, which has been found to be safe and effective in the diagnosis of TB in the available published studies. Ethambutol is known to be taken up specifically by tubercular lesions. This forms the basis of using Tc-99m labelled ethambutol for imaging TB lesions. An added advantage would be its ability to differentiate tubercular from malignant and fungal lung lesions that are the usual differentials in patients suspected of having TB. Most of the studies involving ethambutol have been done in skeletal TB and its validation in other forms of TB is still awaited. Recently the role of PET-CT has also been explored in human studies using 11C Rifampicin to study the antibiotic uptake in tubercular lesions. This review summarizes the available evidence regarding diagnosis of TB by radiolabeled antibiotic imaging to emphasize the need for accelerated research in the fight against TB.

99mTc-Ethambutol Scintigraphy with Single-Photon Emission Computed Tomography/Computed Tomography in Lymph Node Tuberculosis: An Initial Experience.

Purpose of the Study: The purpose of the study is to evaluate 99mTc-labeled ethambutol (99mTc-EMB) as a potential diagnostic agent in lymph node tuberculosis (LNTB). Materials and Methods: A prospective pilot study was done at All India Institute of Medical Sciences, New Delhi. We included adult consenting patients who were diagnosed with LNTB and were either treatment naïve or had just started treatment. Patients were injected with 10-15 mCi of 99mTc-EMB. Whole-body anteroposterior planar imaging was done from 15 min after injection at serial intervals till 4-6 h along with one single-photon emission computed tomography-computed tomography (SPECT-CT) imaging with the help of a dual-head SPECT-CT gamma camera. The uptake of 99mTc-EMB was analyzed and corroborated with clinicoradiological findings. Results: Between January 2019 and November 2020, we recruited 23 patients who underwent 99mTc-EMB, and 19 scans were interpretable and considered for analysis. Cervical lymphadenopathy was the most common presentation (13, 68.42%), followed by mediastinal (9, 47.36%) and abdominal (4, 21.05%) nodes. Other involvement included pulmonary (8, 42.1%), gastrointestinal (3, 15.78%), and chest wall abscess and bone marrow deposits in 1 patient each. A positive scan was noted in 7 (53.84%) patients with cervical lymphadenopathy, whereas uptake in abdominal and mediastinal lymph nodes was seen in 1 (25%) and 2 (22.22%) cases, respectively. Uptake in pulmonary lesions was noted in 3 (37.5%), but uptake in hepatic and splenic lesions was not seen. Conclusion: 99mTc-EMB scan can demonstrate drug penetrance in vivo in some patients with LNTB and should be explored further with a larger sample size.

GLP-1-mediated delivery of tesaglitazar improves obesity and glucose metabolism in male mice.

Dual agonists activating the peroxisome proliferator-activated receptors alpha and gamma (PPARɑ/ɣ) have beneficial effects on glucose and lipid metabolism in patients with type 2 diabetes, but their development was discontinued due to potential adverse effects. Here we report the design and preclinical evaluation of a molecule that covalently links the PPARɑ/ɣ dual-agonist tesaglitazar to a GLP-1 receptor agonist (GLP-1RA) to allow for GLP-1R-dependent cellular delivery of tesaglitazar. GLP-1RA/tesaglitazar does not differ from the pharmacokinetically matched GLP-1RA in GLP-1R signalling, but shows GLP-1R-dependent PPARɣ-retinoic acid receptor heterodimerization and enhanced improvements of body weight, food intake and glucose metabolism relative to the GLP-1RA or tesaglitazar alone in obese male mice. The conjugate fails to affect body weight and glucose metabolism in GLP-1R knockout mice and shows preserved effects in obese mice at subthreshold doses for the GLP-1RA and tesaglitazar. Liquid chromatography-mass spectrometry-based proteomics identified PPAR regulated proteins in the hypothalamus that are acutely upregulated by GLP-1RA/tesaglitazar. Our data show that GLP-1RA/tesaglitazar improves glucose control with superior efficacy to the GLP-1RA or tesaglitazar alone and suggest that this conjugate might hold therapeutic value to acutely treat hyperglycaemia and insulin resistance.

Isolated Pancreatic Metastasis From Choroidal Melanoma After 10 Years of Enucleation Mimicking Neuroendocine Tumor on 68Ga-DOTANOC PET/CT.

Isolated pancreatic metastasis from choroidal melanoma is a rare phenomenon. We describe a case of a 38-year-old woman who underwent enucleation surgery for right choroidal melanoma and subsequently developed lesions in the pancreas 10 years after enucleation, which were depicted on Ga-DOTANOC PET/CT and confirmed to be metastasis from choroidal melanoma on surgical histopathology.

Solitary Subcutaneous Tissue Metastasis as Recurrence in a Case of Primary Angiosarcoma of Breast: Findings on 18F-Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography.

Primary angiosarcomas of the breast are rare tumors, with a fatal outcome. We present a rare case of an operated primary angiosarcoma of the right breast in a 20-year-old female who showed disease recurrence in the right posterior arm subcutaneous tissue on 18F-fluorodeoxyglucose positron emission tomography-computed tomography after 1 year of surgery without any other visceral metastasis.

Extensive Extranodal Cutaneous Lymphomatous Involvement in a Case of Adult T-Cell Lymphoma - Advantage of 18F Fluorodeoxyglucose Positron-emission Tomography-Computed Tomography over Computed Tomography.

Diffuse extranodal cutaneous lymphomatous involvement is a unique presentation in a case of adult T-cell lymphoma. We present the case of a 26-year-old female who presented with erythematous rashes with subsequent evaluation with 18F fluorodeoxyglucose positron-emission tomography-computed tomography showing enlarged inguinal and axillary lymph nodes, and biopsy findings from the inguinal lymph nodes were suggestive of adult T-cell lymphoma.

Paraneoplastic Cutaneous Mucinosis as Initial Presentation of Recurrence in an Operated Case of Carcinoma Ovary: True Extent of Recurrent Metastatic Disease Unveiled on 18F Fluoro-D-Glucose Positron Emission Tomography-Computed Tomography.

Ovarian carcinoma is associated with many cutaneous and paraneoplastic manifestations. We present a case of 52-year-old female who underwent total abdominal hysterectomy with bilateral salpingo-oophorectomy for epithelial origin ovarian carcinoma. She presented with skin rashes over the face and neck region after 2 years. 18F-fluoro-D-glucose positron emission tomography-computed tomography scan revealed recurrent metastatic retroperitoneal lymph nodes.