Occult breast primary malignancy presenting as isolated axillary lymph node metastasis — early detection of primary site by 18F-FDG PET/CT

Breast cancer patients rarely present with isolated axillary lymph node metastasis without any clinical or radiological evidence of primary tumor. Identification of the primary site of tumor helps in planning appropriate patient management which has definite impact on patient’s survival. We present here a case of 30-year-old female who presented with isolated right axillary lymph node metastasis with no evidence of primary tumor clinically. Conventional imaging modalities were negative for primary site. She underwent whole body 18F-Flurodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) and it contributed significantly in early detection of occult primary tumor in right breast

Preoperative characterization of indeterminate large adrenal masses with dual tracer PET-CT using fluorine-18 fluorodeoxyglucose and gallium-68-DOTANOC: initial results

PURPOSEWe aimed to evaluate the usefulness of dual tracer positron emission tomography-computed tomography (PET-CT) with flourine-18 fluorodeoxyglucose (18F-FDG) and gallium-68 [1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid]-1-NaI3-octreotide (68Ga-DOTANOC) in preoperative characterization of large indeterminate adrenal masses.MATERIALS AND METHODSTen patients (four males, six females; median age, 35 years) with indeterminate, large (≥4 cm) adrenal masses were included in this prospective study. All patients underwent both 18F-FDG PET-CT and 68Ga-DOTANOC PET-CT within one week. Images were evaluated both visually and semi-quantitatively, with standardized uptake value (SUVmax) and SUVratio (SUVmax) of tumor/SUVmax) of mediastinum). Based on differential uptake pattern on 18F-FDG and 68Ga-DOTANOC, lesions were classified as cortical (18F-FDG>68Ga-DOTANOC), medullary (68Ga-DOTANOC>18F-FDG), or indeterminate (18F-FDG=68Ga-DOTANOC). Histopathology was taken as reference standard. Receiver operating characteristic (ROC) analysis was performed to find a cut-off of SUVmax) and SUVratio to differentiate cortical and medullary lesions.RESULTSOn histopathology, eight lesions were adrenocortical carcinomas, one was benign pheochromocytoma, and one was malignant pheochromocytoma. Visually, 18F-FDG PET-CT was positive in all ten lesions, while 68Ga-DOTANOC PET-CT was positive in two, both of which were pheochromocytomas. On SUVmax) based analysis, nine lesions were cortical and one was medullary. On ROC analysis, a SUVmax) cut-off of > 2.3 was obtained for 18F-FDG PET-CT and 3.6 for 68Ga-DOTANOC PET-CT for differentiating adrenal cortical and medullary lesions. The cut-off for SUVratio was 4.5 on 18F-FDG PET-CT and 11.1 on 68Ga-DOTANOC PET-CT.CONCLUSIONThese preliminary results demonstrate that dual tracer PET-CT using 18F-FDG and 68Ga-DOTANOC could be informative in the preoperative characterization of large indeterminate adrenal masses

Hybrid SPECT-CT with 99mTc-labeled red blood cell in a case of blue rubber bleb nevus syndrome: added value over planar scintigraphy

Blue rubber bleb nevus syndrome (BRBNS) is a rare vascular anomaly syndrome consisting of multifocal venous malformations most commonly involving the skin, soft tissues, and gastrointestinal tract. The gastrointestinal lesions of BRBNS are the most clinically relevant malformations and carry a significant potential for serious bleeding. William Bennet Bean first coined the term “BRBNS” in 1958, and only 200 cases have been described since then (1). A few reports have described the use of 99mechnetium (99mTc)-labeled red blood cell (RBC) planar scintigraphy in BRBNS patients to localize the site of bleeding (2–5). To the best of our knowledge, however, the role of single-photon emission computed tomography-computed tomography (SPECT-CT) in examining such patients has not been evaluated. Here, we report the value of 99mTc-labeled RBC hybrid SPECT-CT over planar scintigraphy alone in a patient with BRBNS

Primary penile lymphoma: the use of PET-CT for accurate staging and response monitoring

Primary penile lymphoma is an extremely rare neoplasm. We present a case of 63-year-old man with painless diffuse pe- nile swelling and retention of urine. Biopsy from the penile swelling demonstrated CD20+ diffuse large B-cell lymphoma. Staging was performed using fluorine-18-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET-CT) and revealed a FDG avid penile mass with enlarged and FDG avid multiple inguinal and aortocaval lymph nodes. A follow-up FDG PET-CT scan after eight cycles of combina- tion chemotherapy showed complete remission of the dis- ease. Thus, FDG PET-CT should be integrated in management protocols of rare primary penile lymphoma

SPECT-CT for characterization of extraosseous uptake of 99mTc-methylene diphosphonate on bone scintigraphy

Bone scintigraphy is a sensitive and popular method for imaging a wide array of benign or malignant skeletal abnormalities. However, the uptake of tracers used for bone scintigraphy may be observed in various extraosseous sites, thereby limiting its specificity. It is difficult to correctly localize such sites of uptake on planar bone scintigraphy alone. The addition of hybrid single-photon emission computed tomography-computed tomography (SPECT-CT) under such circumstances is very useful. The present essay illustrates the commonly encountered extraosseous uptake of 99mTc-methylene diphosphonate (MDP) and the usefulness of hybrid SPECT-CT in clarifying 99mTc-MDP uptake