Recurrent Medullary Thyroid Carcinoma on 68Ga–Prostate-Specific Membrane Antigen PET/CT

Abstract

The prostate-specific membrane antigen (PSMA) is highly expressed in prostate cancer cells. Few other malignancies have shown expression of PSMA. We present a case of 35-year-old man with medullary thyroid carcinoma, post total thyroidectomy and bilateral neck dissection, now presenting with rising calcitonin levels (doubling time 9 months) and local neck recurrence with negative I-MIBG scan. We decided to perform Ga-PSMA-HBED-CC PET/CT scan to assess PSMA expression and explore the therapeutic option in view of rising serum calcitonin. It revealed intense PSMA uptake in the soft tissue mass in left thyroid bed and cervical lymph nodes.

PSMA radioligand therapy for solid tumors other than prostate cancer: background, opportunities, challenges, and first clinical reports

“…PSMA tracer uptake on PET/CT imaging of thyroid cancer has been described in several case reports and subsequent larger prospective studies (Fig. 2) [63][64][65][66][67][68][69][70][71][72][73][74][75]. Overall, in DTC patients, PSMA tracer uptake seemed to differ between primary/recurrent lesions and metastatic lesions.…”

“…Therefore, it may appear as if more tumors are PSMA avid, or have higher SUV values than is actually the case. In addition, relevant data such as PSMA tracer uptake (SUVmax) was frequently not reported [40,49,50,64,67,69,107,130,131].…”

“…Therefore, especially metastatic DTC patients might have sufficient tracer uptake to be eligible for PSMA-RLT. PSMA uptake in ATC and MTC patients was only described in few patients, with relatively low SUVmax values (primary tumor uptake 4.5-6) [69][70][71][72][73]. Of these, Arora et al reported a tumor/liver ratio > 2 in some MTC patients, indicating the possible eligibility of these patients for PSMA-RLT [69].…”

Lesion-to-background ratio threshold value of SUVmax of simultaneous [68Ga]Ga-PSMA-11 PET/MRI imaging in patients with prostate cancer

“…These factors also have a profound impact on prognosis because both extracapsular extension and seminal vesicle invasion are associated with an increased risk of recurrence and lymph node and bone metastasis. Because of the high sensitivity of PSMA, it is easier to detect hidden residual and recurrent focals [5,22,23,25,26,[29][30][31][32]. [ 68 Ga]Ga-PSMA PET was superior to MRI in determining distant metastasis in patients with moderate-to high-risk PCa.…”

Nonspecific uptake of 68Ga-prostate-specific membrane antigen in diseases other than prostate malignancy on positron emission tomography/computed tomography imaging: A pictorial assay and review of literature

“…[ Table 2 ]. [ 21 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 ] The 68 Ga-labeled PSMA avidity in these various nonprostatic malignancies has been ascribed to the PSMA expression in the endothelial cells of the tumor neovasculature.…”