case_images: PMC11421938_01
case_images: Piflufolastat F-18 PET/CT: (a-c) axial and (d) coronal images showing heterogeneous avidity of radiotracer in the enlarged prostate gland (arrow, a), enlarged pelvic sidewall lymph node with radiotracer avidity (arrow, b), numerous liver lesions showing no or minimal radiotracer avidity (c), and a lytic lesion at the right side of the L4 vertebral body with radiotracer avidity (arrow, d). The findings represent heterogeneous uptake/PSMA expression across the primary tumor and various sites of metastatic disease, consistent with the mixed histology of this patient's disease.
case_images: CRIONM2024-7998149.001.jpg
case_images: PMC11421938_01_CRIONM2024-7998149.001.jpg
case_images: fig1
case_images: A prostate-specific membrane antigen positron emission tomography (PSMA-PET) scan was obtained with uptake in the prostate (lean body mass-corrected standardized uptake value [SUVmax]: 13.7), multiple avid retroperitoneal and pelvic lymph nodes (SUVmax range: 4.3-8.4), and lytic foci within the left superior pubic ramus and L4 vertebral body (SUVmax range: 4.2-6.5) (Figure 1).
case_images: (a) CT images: postcontrast (A-C) axial and (D) coronal images showing the significantly enlarged heterogeneous prostate gland with irregular borders (thick arrow, A) and significant stranding involving the mesorectum (thin arrows, A) with associated rectal wall thickening. Presacral soft tissue involvement characterized as significant stranding is also noted (thin arrow, B) with associated left pelvic side wall enlarged lymph node (thick arrow, B). The findings are suggestive of infiltrative prostate cancer involving extraprostatic adjacent tissues with local extension with metastatic adenopathy. (C) Numerous hypoattenuating liver lesions likely represent bilobar hepatic metastatic disease. A lytic metastatic bone lesion with associated mild pathologic fracture is also noted at the right side of the L4 vertebral body (arrow, D). (b) MRI images: (A) transverse T2-weighted fat-suppressed single-shot echo train spin echo, (B) T1-weighted in-phase spoiled gradient echo, (C) diffusion-weighted, and (D) postgadolinium hepatic venous phase T1-weighted fat-suppressed three-dimensional gradient echo images show numerous bilobar metastatic liver lesions with high T2 signal, low T1 signal, high diffusion signal, and postcontrast rim type of enhancement with associated mild internal hypoenhancement compared to the background liver.
case_images: CRIONM2024-7998149.002.jpg
case_images: PMC11421938_01_CRIONM2024-7998149.002.jpg
case_images: fig2
case_images: Computed tomography (CT) imaging of the abdomen and pelvis was notable for worsening pelvic adenopathy and lytic metastases, a possible L4 compression fracture, and innumerable liver lesions (Figure 2(a)). An MRI of the abdomen confirmed innumerable hepatic lesions and demonstrated extensive osseous metastatic disease (Figure 2(b)).
case_images: Liver and prostate biopsy, H&E, and immunohistochemistry: prostate core biopsy (a, b) shows conventional prostatic acinar adenocarcinoma with areas of poorly formed glands and infiltrative single cells (arrow) immediately adjacent to small-cell carcinoma in sheets and cords (bracket). On higher power (c), the small-cell carcinoma component demonstrates crush artifact, high nuclear to cytoplasmic ratios, and nuclear molding. Liver lesions (d) biopsied 2 months after the prostate biopsy shows nests of small-cell carcinoma invading through liver parenchyma. In the prostate biopsy (e), the nuclei of infiltrating acinar cell adenocarcinoma stains strongly positive for NKX3.1, a sensitive and specific prostate marker, and the adjacent small-cell carcinoma (f) has strong cytoplasmic granular staining for synaptophysin, a sensitive marker for neuroendocrine differentiation. The liver lesions (g) also stain positive for synaptophysin and strongly positive for INSM1 (h), a highly sensitive and specific neuroendocrine marker, consistent with metastasis of the prostate cancer with neuroendocrine differentiation and small-cell features.
case_images: CRIONM2024-7998149.003.jpg
case_images: PMC11421938_01_CRIONM2024-7998149.003.jpg
case_images: fig3
case_images: TTF-1 and focally positive for chromogranin, and Ki-67 labeling index was > 90%; staining was negative for PSA, NKX3.1, CDX2, PAX8, and GATA-3 (Figure 3). In this context, the patient's initial prostate biopsy was re-reviewed, with additional immunostains, and found to show both conventional high-grade acinar prostate adenocarcinoma as well as a component of small-cell carcinoma (Figure 3). The hospitalization was complicated by the development of a large bowel obstruction secondary to prostatic mass invasion of the rectum ultimately requiring palliative surgical intervention with a diverting ostomy.