Abstract
241878
Introduction: Splenic lesions are rare, usually detected incidentally in asymptomatic patients. Imaging characteristics are therefore crucial for decision-making. We present 4 cases highlighting the role of PET CT in evaluating splenic lesions.
Methods: Case 1. A 77-year-old male presented with abdominal pain in 2021.18F-FDG PET-CT revealed multiple hypermetabolic foci in the enlarged spleen and multiple hypermetabolic lymph nodes. Biopsy revealed follicular lymphoma. A post-treatment 18F-FDG PET-CT in January 2024 demonstrated complete resolution of splenic lesions but new hypermetabolic lymph nodes (Figure 1).
Case 2. A 52-year-old female with a history of serous papillary uterine tumor surgically managed in 2002 presented with abdominal pain in 2023. 18FDG PET-CT showed a splenic mass with hypermetabolic calcified nodules and lymph nodes (fig. 2). Surgical pathology revealed moderately differentiated metastases in the spleen containing psammoma bodies, lymph nodes, and pancreatic tail. Immunostains were positive for gynecologic malignancy. Case 3. A 39-year-old male with a history of testicular seminoma, status post orchiectomy was detected with splenic masses on surveillance CT in February 2023 which appear enlarged on a CT in September 2023. 18F-FDG PET-CT demonstrated hypermetabolic hypoattenuating splenic lesions and hypermetabolic retroperitoneal nodes (Figure 3). Fine needle biopsy of the spleen revealed a granulomatous lesion. Case 4: A 55-year-old male underwent a laparoscopic spleen-sparing distal pancreatectomy for a pancreatic neuroendocrine tumor (NET). The postoperative 68Ga DOTATATE PET-CT showed central splenic photopenia corresponding to hypoattenuation on contrast-enhanced CT and peripheral tracer avid tissue suspicious for malignancy. (Figure 4).
Results: The spleen contains lymphocyte-rich white pulp centrally and red pulp rich in venous sinuses peripherally. Hemangiomas are the most common benign tumors of the spleen and lymphoma is the most common malignancy. 18F-FDG PET-CT narrows the vast differentials for splenic masses.18F-FDG avid lesions are primarily infectious/granulomatous lesions, metastases, and primary malignancies. The high avidity of 68Ga DOTATATE for somatostatin receptor-expressing tissues leads to equivocal findings in somatostatin receptor-rich organs. Lymphomatous involvement of the spleen can manifest as splenomegaly, diffuse infiltration, multiple nodules, and rarely as solitary nodules.
In Case 1, hypermetabolic lesions in the enlarged spleen and hypermetabolic lymph nodes on both sides of the diaphragm were suggestive of lymphoma.
Despite its high vascularity, splenic metastases are rare with only about 7% of patients with advanced cancers developing splenic metastases, likely due to an unfavorable internal milieu. Splenic metastases are most commonly from breast, lung, and ovarian cancer, melanoma, and colon cancer. The most common findings are a hypoattenuating lesion with rare calcifications and enhancement.
Uterine papillary serous adenocarcinoma may contain calcifying psammoma bodies. 18FDG avid calcified splenic lesions and retroperitoneal lymph nodes in case 2 were therefore suspicious for metastases as opposed to granulomatous/infectious pathology.
In case 3 the presence of retroperitoneal lymph nodes and enlarging splenic nodules increases the suspicion of metastases since 9-11% of patients with seminomas develop atypical metastases. However, tissue sampling revealed granulomatous disease.
2-5% of patients develop splenic infarcts following spleen-sparing pancreatectomies majority of which are asymptomatic. Non-enhancing hypoattenuating areas denote infarction on CT. In case 4, 68Ga DOTATATE avid tissue around the non-functioning spleen is suspicious of malignancy. The location of the tracer avid tissue, negative surgical margins, and MRI features favored residual splenic tissue.
Conclusions: PET CT is crucial for oncologic decision-making and directs further evaluation, especially with rare presentations.
In this issue
Jump to section
Related Articles
Cited By...
- No citing articles found.