Adrenal collision tumor diagnosed by F-18 fluorodeoxyglucose PET/CT

Collision of Solid Pseudopapillary Tumor and Neuroendocrine Tumor of the Pancreas on 18F-FDG PET/CT

ABSTRACT

We report a rare case of pancreatic collision tumor of solid pseudopapillary tumor and neuroendocrine tumor in a 43-year-old woman. A pancreatic mass was found by abdominal ultrasound. A mainly cystic mass with solid component progressive enhancement was revealed using abdominal enhanced CT. Staging 18F-FDG PET/CT demonstrated a pancreatic tail mass with an increased uneven 18F-FDG uptake. Distal pancreatectomy was performed. Postoperatively, the mass was diagnosed as pancreatic collision tumor of solid pseudopapillary tumor and neuroendocrine tumor.

Practical Approach to Adrenal Imaging

Various pathologies can affect the adrenal gland. Noninvasive cross-sectional imaging is used for evaluating adrenal masses. Accurate diagnosis of adrenal lesions is critical, especially in cancer patients; the presence of adrenal metastasis changes prognosis and treatment. Characterization of adrenal lesions predominantly relies on morphologic and physiologic features to enable correct diagnosis and management. Key diagnostic features to differentiate benign and malignant adrenal lesions include presence/absence of intracytoplasmic lipid, fat cells, hemorrhage, calcification, or necrosis and locoregional and distant disease; enhancement pattern and washout values; and lesion size and stability. This article reviews a spectrum of adrenal pathologies.

Hematopoietically Active Adrenal Myelolipoma Mimicking Breast Cancer Metastasis

A 66-year old woman had a left breast mass. Biopsy showed invasive ductal carcinoma. A PET/CT scan demonstrated hypermetabolism in the left breast and atypical heterogeneously increased uptake throughout the skeleton as well as a minimally FDG-avid right adrenal myelolipoma. PET/CT 4 months later after 6 cycles of neoadjuvant chemotherapy demonstrated increased size and FDG avidity of this adrenal mass concerning for metastasis and uniformly increased skeletal FDG avidity. Biopsy demonstrated adrenal myelolipoma. The growth and increased FDG avidity of the adrenal myelolipoma were due to the action of colony-stimulating factors on the tumor's hematopoietic component.

An exceedingly rare adrenal collision tumor: adrenal adenoma-metastatic breast cancer-myelolipoma

Adrenal collision tumors (ACTs), in which distinct tumors coexist without histological intermingling in the same adrenal gland, are rare and their actual prevalence is unknown. ACTs commonly consist of adrenal cortical adenoma, myelolipoma, or metastatic malignant tumor. We report a 58-year-old woman with a past history of breast cancer, who presented with a 1 month history of fevers, chills, and abdominal fullness. The physical examination and the laboratory data including endocrine studies were unremarkable. Computed tomography of the abdomen showed a right adrenal gland mass, and a laparoscopic right adrenalectomy was performed. Histological and immunohistochemical examinations revealed three distinct tumors: an adrenal cortical adenoma, a myelolipoma, and metastatic breast tumors. Breast cancer metastases are rare in the adrenal gland and exist as ACTs only in exceptionally rare cases. To our knowledge, this is the first reported case of coexisting metastatic breast tumors, adrenal adenoma, and myelolipoma in the same adrenal gland.

Practical Approach to Adrenal Imaging

Various pathologies can affect the adrenal gland. Noninvasive cross-sectional imaging is used for evaluating adrenal masses. Accurate diagnosis of adrenal lesions is critical, especially in cancer patients; the presence of adrenal metastasis changes prognosis and treatment. Characterization of adrenal lesions predominantly relies on morphologic and physiologic features to enable correct diagnosis and management. Key diagnostic features to differentiate benign and malignant adrenal lesions include presence/absence of intracytoplasmic lipid, fat cells, hemorrhage, calcification, or necrosis and locoregional and distant disease; enhancement pattern and washout values; and lesion size and stability. This article reviews a spectrum of adrenal pathologies.

Possible ACTH-independent, cortisol-secreting and DHEA-secreting metastatic hepatocellular carcinoma causing Cushing's syndrome

Cortisol production by hepatocellular carcinoma (HCC) has not been previously reported and dehydroepiandrosterone (DHEA) secretion by HCC is rare. We report a case of a 53-year-old woman admitted with dyspnoea and headache. Serum cortisol by immunoassay (IA) was 42.3 μg/dL, urine free cortisol (UFC) by liquid chromatography mass spectrometry (LC/MS/MS) was 106.1 μg/24 h, serum DHEA by LC/MS/MS was 4886 ng/mL, serum DHEA-S by LC/MS/MS was 4477 ng/mL and plasma adrenocorticotrophic hormone (ACTH) by IA was 10 pg/mL. CT showed likely HCC metastatic to the left adrenal gland, brain and lungs. Liver and adrenal gland biopsies confirmed HCC. ACTH tumour staining was negative. High serum and UFC levels and high serum DHEA and DHEA-S with low-normal plasma ACTH and negative tumour ACTH staining suggested ACTH-independent ectopic Cushing's syndrome (CS); cortisol and DHEA being likely secreted by the HCC. To the best of our knowledge, this is the first reported case of HCC associated with CS.

Imaging Features of Various Adrenal Neoplastic Lesions on Radiologic and Nuclear Medicine Imaging

OBJECTIVE

The purpose of this review is to describe the features of diverse adrenal neoplastic lesions on radiologic and nuclear medicine imaging.

CONCLUSION

Various neoplastic lesions with or without malignant potential can occur in the adrenal gland. Knowledge of imaging features of adrenal lesions on radiologic and nuclear medicine imaging will facilitate differential diagnosis and assessment of malignant potential.

Metabolic and anatomic characteristics of benign and malignant adrenal masses on positron emission tomography/computed tomography: a review of literature

PET/CT with (18)F-fluorodeoxyglucose (FDG) or using different radiocompounds has proven accuracy for detection of adrenal metastases in patients undergoing cancer staging. It can assist the diagnostic work-up in oncology patients by identifying distant metastases to the adrenal(s) and defining oligometastatic disease that may benefit from targeted intervention. In patients with incidentally discovered adrenal nodules, so-called adrenal "incidentaloma" FDG PET/CT is emerging as a useful test to distinguish benign from malignant etiology. Current published evidence suggests a role for FDG PET/CT in assessing the malignant potential of an adrenal lesion that has been 'indeterminately' categorized with unenhanced CT, adrenal protocol contrast-enhanced CT, or chemical-shift MRI. FDG PET/CT could be used to stratify patients with higher risk of malignancy for surgical intervention, while recommending surveillance for adrenal masses with low malignant potential. There are caveats for interpretation of the metabolic activity of an adrenal nodule on PET/CT that may lead to false-positive and false-negative interpretation. Adrenal lesions represent a wide spectrum of etiologies, and the typical appearances on PET/CT are still being described, therefore our goal was to summarize the current diagnostic strategies for evaluation of adrenal lesions and present metabolic and anatomic appearances of common and uncommon adrenal lesions. In spite of the emerging role of PET/CT to differentiate benign from malignant adrenal mass, especially in difficult cases, it should be emphasized that PET/CT is not needed for most patients and that many diagnostic problems can be resolved by CT and/or MR imaging.

Adrenal collision tumors and their mimics: multimodality imaging findings

Adrenal collision tumors (ACTs) refer to coexistence of two adjacent, but histologically distinct neoplasms involving the adrenal gland without histologic admixture at interface. ACTs include adenoma with myelolipoma, adenoma with metastases, hemangioma with adenoma, and adrenocortical carcinoma with myelolipoma. In addition, hemorrhage into a pre-existing adrenal mass can mimic an ACT, and it is important to differentiate these two pathologies. Accurate characterization of ACTs is difficult, but critical, for correct staging of patients with malignancies and to guide percutaneous biopsy. Magnetic resonance imaging (MRI) and multidetector computed tomography imaging techniques may depict different tumor components separately; however, biopsy may be required in selected patients for confirmation. [¹⁸F]Fluorodeoxyglucose-positron emission tomography (PET) shows increased uptake in the malignant component of ACTs, and guides percutaneous biopsy. Even in patients requiring percutaneous biopsy for a definite diagnosis, imaging findings can help in guiding the appropriate component to be biopsied. Knowledge of imaging findings of different ACTs and their mimics on MRI, computed tomography, and PET help in optimal patient management.