Penile metastasis from prostate adenocarcinoma is an exceptionally rare manifestation of advanced disease. We report the case of a 64-year-old man with biopsy-proven prostatic adenocarcinoma (cT3bN1M1, Gleason 4+4=8), diagnosed in 2020 with an initial PSA of 122.85 ng/mL. The most remarkable finding was intense, diffuse, and homogeneous PSMA uptake throughout the corpora cavernosa along the entire penile shaft (SUVmax=76.9). Histopathologic examination confirmed metastatic prostatic adenocarcinoma (Grade Group 3, Gleason 4+3=7), involving 100% of the sampled penile tissue. This case illustrates an unusual pattern of diffuse penile involvement, likely reflecting advanced hematogenous or retrograde venous dissemination rather than focal metastatic deposits. It underscores the importance of careful evaluation of the external genitalia on PSMA PET/CT and highlights that penile metastases may present as diffuse, highly PSMA-avid infiltration in advanced prostate cancer.

Sarcoidosis is a multisystem granulomatous disorder of unknown etiology. Despite refinements in diagnostic modalities, it remains a diagnosis of exclusion. We report a representative case of systemic sarcoidosis in a 31-year-old man presenting with severe heart failure. Whole-body FDG PET/CT effectively visualized the systemic disease burden, while simultaneous cardiac FDG PET/MRI provided a precise correlation between myocardial metabolic activity and structural injury. This case illustrates the significant clinical utility of multimodality imaging in providing a comprehensive assessment of the extent and activity of systemic sarcoidosis.

An 18F-MFBG PET/CT scan was conducted to evaluate the therapeutic response following treatment with chemotherapy, surgery, and radiotherapy. This study demonstrated increased 18F-MFBG accumulation in the right perirenal space, accompanied by a cloud-like shadow on the corresponding CT images, which was within the radiation therapy field. The lesion remained positive on subsequent follow-up 18F-MFBG PET/CT imaging. This abnormal MFBG accumulation was within the radiation therapy field. Based on the clinical history, this persistent 18F-MFBG uptake was considered to be related to prior radiotherapy, and should be considered in the differential diagnosis.

⁶⁸Gallium NODAGA-JR11, a somatostatin receptor (SSTR) antagonist, exhibits superior sensitivity in detecting hepatic metastases of neuroendocrine tumors compared with the agonist tracer ⁶⁸Ga-DOTANOC PET/CT. In the presented case of rectal neuroendocrine tumor, both tracers identified the primary lesion and regional lymph node involvement; however, NODAGA-JR11 PET/CT revealed multiple hepatic metastases not visualized on DOTANOC imaging, resulting in disease upstaging. The enhanced lesion detection is attributed to the antagonist’s ability to bind a greater number of receptor sites and reduced hepatic background uptake. These findings highlight the potential impact of NODAGA-JR11 PET/CT on clinical staging and therapeutic decision-making in metastatic neuroendocrine tumors.

Endometriosis is a chronic condition in reproductive-age women, and diagnosis can be delayed for 4–11 years due to nonspecific symptoms and limited imaging. This underscores the need for new methods to overcome these diagnostic challenges. Fibroblast activation protein, strongly expressed in the perilesional stroma of endometriotic lesions, is a promising PET target. We included 8 women who underwent ⁶⁸Ga-FAPI-04 PET/CT for cyclic pelvic or extrapelvic pain and solid nodular lesions, later histopathologically confirmed as endometriosis. In these patients, we showed the targeting diagnostic potential of FAPI PET/CT and endometriotic foci with high accuracy compared with other imaging methods.

A 66-year-old man with inoperable malignant scalp melanoma, refractory to immunotherapy, underwent ^99mTc-HYNIC-TOC SPECT/CT for evaluating the possibility of radioligand therapy with ¹⁷⁷Lu-DOTATATE, which demonstrated no tracer uptake in scalp lesions, precluding ¹⁷⁷Lu-DOTATATE therapy. Subsequent disease progression prompted ^99mTc-FAPI-46 SPECT/CT, which showed intense tracer uptake in lesions and prompted radioligand therapy with ¹⁷⁷Lu-FAPI-2286. After 4 cycles of treatment, all lesions showed regression and he was referred for tumor resection. This case illustrates the clinical utility of FAPI-based theranostic and shows ^99mTc-FAPI SPECT/CT can directly inform targeted radioligand therapy using ¹⁷⁷Lu-FAPI, thereby expanding therapeutic options in melanoma management.