Osteoblastic bone metastases from neuroendocrine tumor (NET) of unknown origin detected by 18fluorocholine PET/CT and its comparison with 68gallium-DOTATOC PET/CT

Abstract

Rationale:Choline (CH) positron emission tomography (PET)/computed tomography (CT) with fluorine 18 (18F) CH is increasingly used not only to evaluate patients with biochemically recurrent prostate cancer but also to assess metastatic lesions that are difficult or impossible to identify using more conventional modalities. Our experience with CH PET/CT has shown that it can also be used for many other malignancies.Presenting concerns:A 71-year-old male with a neuroendocrine tumor (NET) of unknown origin showed osteoblastic bone metastases positive to 18F-CH PET.Interventions:Diffuse bone and liver metastases were 68gallium-DOTATOC PET-positive with only mild uptake on 18FDG PET/CT. An increased prostate specific antigen (8 μg/L) gave rise to a suspicion of concurrent prostate cancer and the patient underwent 18F-CH PET/CT which showed diffuse uptake in the bone. A CT-guided bone biopsy confirmed osteoblastic bone metastases from NET.Outcomes:Given the aggressiveness of the tumor, the patient underwent treatment with temozolomide from July 2015 to December 2015, maintaining stable disease. However, progression was documented in January 2016 and the patient was enrolled onto a phase II peptide receptor radionuclide therapy retreatment trial, which is currently ongoing.Main lesson:Our study highlights that NETs should be taken into consideration in the differential diagnosis of osteoblastic bone metastases showing 18F-CH uptake. A prognostic role for this imaging technique can also be hypothesized.

Neuroendocrine Differentiation of Prostate Cancer—An Intriguing Example of Tumor Evolution at Play

“…NEPC has been shown to progress rapidly, and metastasize primarily to the visceral organs and tissues [61,75]. However, a few reports have also suggested that NEPC metastasizes to the bone [20,76,77,78]. Common features revealed by tumor staining indicate that NEPC is poorly differentiated, displays rosette, swirl or organoid patterns and possesses basophilic appearance, amphiphilic cytoplasm and prominent nucleoli [65,79,80].…”

Metástasis en Hueso Malar de Tumor Neuroendocrino Oncocítico Pulmonar

“…Los bifosfonatos inhiben la reabsorción ósea, disminuyendo la hipercalcemia tumoral además de efecto analgésico. La osteonecrosis, efecto secundario conocido, en fase de infección activa, implica un diagnóstico diferencial complejo con las propias metástasis craneofaciales, ya que muchos pacientes han recibido previamente el tratamiento por otros focos óseos [3][4][5][6] . La diana ósea metastásica craneofacial más frecuente es la mandíbula en zona de molares, área con gran aporte vascular y un remanente de médula ósea hematopoyética en adultos 4 .…”

“…Otras técnicas de medicina nuclear menos específicas para descartar metástasis en TNE son gammagrafía ósea, octreoscan o PET con otros radiotrazadores. Concretando en TNE intratorácicos, se prefiere el 99m Tc-tektrotyd, con gran afinidad por SSTR 2, 3 y 5; altamente expresados en esta localización 1,2,5,14,15 .…”