Clinically occult image revelations of fluorodeoxyglucose positron emission tomography/computed tomography in a peculiar case of sinonasal myeloid sarcoma.

Myeloid sarcoma (MS) is a sparse association of acute myeloid leukemia (AML) with poor overall survival. Sinonasal involvement in MS is rarer and meagerly studied. Recent prospective studies have underlined the importance of positron emission tomography/computed tomography (PET/CT) in disease assessment and relapse detection in extramedullary (EM) AML. Herein, we report a case of MS with sinonasal, orbital, dural, breast, pleural extent of disease with sacral neural foraminal compression. Initial histopathologic and clinicoradiologic features had pointed toward lymphoma. Immunohistochemistry (IHC) on the contrary revealed MS. Although the role of IHC in asserting the diagnosis of MS is remarkable, PET/CT surpasses other modalities in early detection of EM sites of involvement, overall assessment of disease burden, targeting therapy, prognostication, and relapse recognition. Inclusion of PET/CT as a baseline imaging modality can be beneficial in tailoring patient management to improve survival and overall quality of life.

Multicentric primary diffuse large B-cell lymphoma in genitourinary tract detected on 18F-F-fluorodeoxyglucose positron emission tomography with computed tomography: An uncommon presentation of a common malignancy.

Primary extranodal lymphomas (ENLs) are lymphomas with no or minor nodal involvement and a dominant extranodal component originating from any organ. Primary ENL originating in the genitourinary tract is extremely rare. Diffuse large B-cell lymphoma (DLBCL) is the most frequent histological subtype in primary genitourinary lymphoma. Lymphomatous involvement of genitourinary system organs is common in the setting of disseminated disease. Herein, we present a unique case of primary multicentric extranodal DLBCL of the urogenital system involving ureter, seminal vesicle, and penis detected on 18fluro-deoxyglucose positron emission tomography with computed tomography, and to the best of our knowledge, it is the first case report with multiorgan involvement within a single (urogenital) organ system in a patient without disseminated disease, i.e., with no other nodal or extranodal organ system involvement.

Incremental Value of FDG PET/CT in Aggressive High Grade B Cell lymphoma with TdT Expression.

High-grade B-cell lymphoma, an aggressive form of Non-Hodgkin's Lymphoma, is known as a double or triple hit lymphoma based on the presence of MYC and BCL2 without or with BCL6 genetic rearrangements, respectively. It carries a poorer prognosis, compared to other variants of B-cell lymphoma, and its management also differs which requires more intensive chemotherapy in contrast to the routine regimen. Terminal deoxynucleotidyl transferase (TdT), a marker of immaturity is commonly expressed in B-cell lymphoblastic leukemia or lymphoma (B cell ALL) which is absent in mature forms of B-cell lymphoma. The TdT is expressed in high-grade B-cell lymphoma; therefore, it poses a classification and management dilemma, which should be accurately differentiated from B-cell ALL and mandates molecular analysis. Herein, we report a case of a 52-year-old female with biopsy reported as high-grade B-cell lymphoma with TdT expression. She was referred for Fluor-deoxyglucose (FDG) Positron Emission Tomography-Computed Tomography (PET/CT) scan for staging in the absence of molecular analysis for B-cell ALL. It was diagnosed as lymphoma on FDG PET/CT based on its characteristic findings of extensive extranodal involvement of multiple organs with no significant lymphadenopathy establishing the incremental value of FDG PET/CT scan, which helped the clinician to arrive at a conclusion.

Pericardial Synovial Sarcoma Followed Up With Contrast-Enhanced PET-CT.

Pericardial synovial sarcoma is an extremely rare tumor, and a challenging diagnosis due to nonspecific diverse presentation requiring a very strong clinical acumen along with an aggressive multimodal approach. Histopathological confirmation remains the gold standard. The optimal management is unclear because of very few cases reported in literature. Herein, we describe the findings on contrast-enhanced FDG PET-CT facilitating the staging, lesion characterization, and timely response assessment to chemotherapy.

Diagnostic importance of contrast enhanced (18)F-fluorodeoxyglucose positron emission computed tomography in patients with tumor induced osteomalacia: Our experience.

AIMS AND OBJECTIVES: To assess the diagnostic utility of contrast-enhanced (18)F-fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET-ceCT) in localization of tumors in patients with clinical diagnosis of tumor-induced osteomalacia (TIO), in correlation with histopathological results. MATERIALS AND METHODS: Eight patients (five male and three female) aged 24-60 (mean 42) years with a clinical diagnosis of TIO were included in this prospective study. They underwent whole body (head to toe) FDG PET-ceCT following a standard protocol on Philips GEMINI TF PET-CT scanner. The FDG PET-ceCT results were correlated with postoperative histology findings and clinical follow-up. RESULTS: All the patients had an abnormal PET-ceCT study. The sensitivity of PET-ceCT was 87.5%, and positive predictive value was 100%. The tumor was located in the craniofacial region in 6/8 patients and in bone in 2/8 patients. Hemangiopericytoma was the most common reported histology. All patients underwent surgery, following which they demonstrated clinical improvement. However, one patient with atypical findings on histology did not show any clinical improvement, hence, underwent (68)Gallium-DOTANOC PET-ceCT scan for relocalization of the site of the tumor. CONCLUSION: The tumors causing TIO are small in size and usually located in obscure sites in the body. Hence, head to toe protocol should be followed for FDG PET-ceCT scans with the inclusion of upper limbs. Once the tumor is localized, regional magnetic resonance imaging can be performed for better characterization of soft tissue lesion. Imaging with FDG PET-ceCT plays an important role in detecting the site of the tumor and thereby facilitating timely management.

Standardization of "In-House fatty meal" methodology for cholescintigraphy.

AIM: This study was aimed at standardizing the "In-House fatty meal" methodology in cholescintigraphy and to determine gall bladder ejection fraction (GBEF) with this standardized meal. MATERIALS AND METHODS: This is a prospective case-control study where 61 patients having right upper quadrant pain and postprandial bloating and 59 healthy volunteers were included. They underwent (99m)Tc-mebrofenin fatty meal cholescintigraphy following a standard protocol. Dynamic acquisitions over 120 min were done, with a fatty meal being given between 45- and 60-min. Gallbladder emptying kinetics was studied by assessing the time activity curves and calculation of GBEFs were made at 30-min, 45-min, and at 60-min and assessed. RESULTS: The GBEF at 30-min was 74.42% ± 8.26% (mean ± standard deviation), at 45-min was 82.61% ± 6.5%, and at 60-min was 89.37% ± 4.48% in the volunteer group. The lower limit of GBEF in volunteers at 30-min was 58%, 45-min was 69%, and at 60-min was 81%. Receiver operating characteristic (ROC) analysis showed that 30-min GBEF provided the best separation between healthy and diseased subjects with an area under curve of 0.952 (95% confidence interval = 0.914-0.989). The lower limit of GBEF at 30-min was 58%. CONCLUSIONS: An in-House standard fatty meal could be a reproducible alternative to cholecystokinin as it is well-tolerated. Based on ROC curve analysis, we propose that 30-min GBEF provides good separation between healthy and diseased people with this in-House fatty meal. Hence, dynamic acquisitions beyond 30-min postingestion of the fatty meal may not be warranted.

Diaphragm and Laryngeal FDG Uptake With Hiccups.

F-FDG PET/CT study is a well-established investigation in diagnosis, treatment evaluation, and follow-up of malignant tumors. It is very important to know the normal biodistribution and physiologic uptake of F-FDG to prevent it from confusing as malignant disease. This article describes unusual but physiological uptake in the laryngeal and diaphragmatic muscles in a patient presenting as metastatic adenocarcinoma with unknown primary having hiccups.