Splenic hamartoma presenting as a "hot spot" on Tc-99m phytate SPECT imaging

Contrast-enhanced sonography with Sonazoid as a new diagnostic tool for splenic hamartoma: a single case report

Detection of reticuloendothelial system (RES) cells is essential for the differential diagnosis of splenic hamartoma. Among the imaging techniques using contrast agents phagocytosed by RES cells, contrast-enhanced ultrasonography (CEUS) with Sonazoid is less invasive and less costly than (99m)Tc-labeled colloid scintigraphy. We report a case of non-symptomatic splenic hamartoma in a 40-year-old woman detected as an abdominal tumor by screening ultrasonography. The tumor was 4 cm in diameter, round, slightly hypoechoic, and associated with a cystic lesion. The tumor region was stained on enhanced computed tomography with prolonged enhancement, while the cystic lesion was not. The mass appeared as mainly isointense with partial hyperintensity on T1-weighted and as a mixed hypo- and hyperintense region on T2-weighted magnetic resonance images. (99m)Tc-labeled colloid scintigraphy demonstrated uptake in only the tumor region. CEUS with Sonazoid revealed that the tumor was mainly hypervascular with non-enhanced areas in the early vascular phase, but the hypervascular region appeared also as a hyperechoic area (indicating microbubble phagocytosis) in the post-vascular phase. Thus, CEUS with Sonazoid revealed all three cardinal features of splenic hamartoma: hypervascularity, presence of RES cells, and tissue heterogeneity. Splenectomy and histopathology confirmed the presence of a splenic hamartoma with associated hematoma. CEUS with Sonazoid is a promising new diagnostic tool for splenic hamartoma.

Multi-modality imaging findings of splenic hamartoma: a report of nine cases and review of the literature

PURPOSE

To investigate the presentation of splenic hamartomas (SHs) on ultrasonography (US), CT and MRI.

METHODS

Nine patients (5 males and 4 females, mean age, 52.8 years) with pathologically proven SHs were included in this study. US, CT and MRI images were analyzed retrospectively, and imaging features were correlated with pathological findings.

RESULTS

SHs appeared solitary lesion (n = 8) and multiple lesions (n = 1) in the present study. (1) In 8 cases of solitary lesion, the lesions appeared as solid nodules or masses with well-defined margins and varying echogenicity (hyperecho = 5, hypoecho = 2, strong echo = 1) on ultrasound. The lesions showed iso-attenuation (n = 3) or slightly hypo-attenuation (n = 4) on unenhanced CT, and calcification were revealed in 3 lesions. MRI showed isointensity (n = 3) or hypointensity (n = 2) on the T1-weighted image, and heterogeneous hypointensity (n = 2), slightly hyperintensity (n = 2) and hyperintensity (n = 1) on the T2-weighted image. The enhanced patterns of SHs showed mild diffuse heterogeneous enhancement (n = 6) and prominent enhancement (n = 1) during arterial phase and above 7 lesions were demonstrated progressive enhancement at delayed phase on enhanced CT. One lesion without any enhancement was revealed in another patient. (2) One case of multiple lesions included 1 cystic lesion with irregular calcification and 7 solid lesions with progressive enhancement on CT images.

CONCLUSIONS

Combination of a variety of imaging modalities could more fully reflect the pathological characteristics and contribute to the diagnosis of SH.

Splenic hamartoma: a case report and clinicopathological analysis of Japanese cases

A 75-year-old man was referred to our department for the treatment of a gastric submucosal tumor-like protrusion which had gradually enlarged over 3 years. After examination with various types of imaging modalities, a splenic mass was diagnosed. Splenectomy was performed because it was difficult to determine preoperatively whether the splenic mass was benign or malignant. The postoperative pathological examination revealed a splenic hamartoma without malignancy. Despite the preoperative examination with advanced diagnostic imaging techniques and equipment, an accurate diagnosis of splenic hamartoma is difficult due to its rarity, lack of specific symptoms, and various inadequacies of radiological imaging techniques. Here we present a rare case of splenic hamartoma and discuss the clinical characteristics obtained from a review of Japanese cases of this rare condition.

"Hamartoma" of the spleen (splenoma) in children

Hamartomas of the spleen or splenomas, are uncommon benign tumorous growths in this organ which have not been well characterized in children. We report four patients, 4 to 11 years old, who had splenomegaly and splenic "hamartomas" associated with different hematologic conditions (refractory microcytic anemia, sickle cell anemia, hereditary spherocytosis, and dyserythropoietic hemolytic anemia). All patients had total splenectomy as a primary therapeutic approach or to lessen their transfusion requirements. In only one patient was a focal splenic mass identified preoperatively with contrasted computed tomography (CT) scans and magnetic resonance imaging (MRI). None of the patients showed a mass by ultrasonography. Gross examination showed enlarged spleens (315-724 g) which on cut surface revealed a single nodule in one and multiple bulging nodules in three specimens. The nodules varied from 1.3 to 7 cm and were indistinct from the surrounding nonlymphoid splenic (i.e., red pulp) parenchyma. Histology of the nodules showed red splenic pulp with variable histiocytic proliferation, focal extramedullary hematopoiesis, lympho-plasmacytosis, fibrosis, and siderotic-calcific deposits. Intranodular small T- and B-cell lymphoid aggregates but no organized secondary follicles or periarteriolar sheaths were seen. Proliferation antigen Ki-67 (Mib-1) immunostains showed a low (< 5%) proliferation index in the nodules and surrounding tissue. Reticulin stains did not show a capsule or border between the normal spleen and the nodules. The critical histologic differential diagnosis for these lesions is with benign vascular tumors. These can be identified by their more disorderly pattern, by immunohistochemistry and by their higher proliferation index. It is our contention that these splenic nodules are not true hamartomas, as they seem to result from remote ischemic or infectious/inflammatory insults, leading to the fibro-inflammatory reaction and deposition of calcium and hemosiderin that is better designated with the descriptive term of splenoma. Review of the literature and our own experience indicates that most children with splenic hamartomas or splenomas as we prefer to call them, have an underlying hematologic disorder likely made worse by a state of hypersplenism that explains the consistent improvement in the blood values after splenectomy.

Tc-99m colloid and Ga-67 imaging of splenic inflammatory pseudotumor correlation with ultrasound, CT, and MRI

Splenic inflammatory pseudotumor is extremely rare and may mimic splenic neoplasms, such as lymphomas or hamartomas, clinically and radiologically. A case of a surgically proved splenic inflammatory pseudotumor is presented in which Tc-99m colloid SPECT and Ga-67 scintigraphy characterized the changes in the spleen, but the findings of ultrasound and unenhanced CT and MRI were nonspecific. This report indicates the utility of radionuclide imaging for diagnosing splenic inflammatory pseudotumor.