Contrast-enhanced ultrasonography in nodular splenomegaly associated with type B Niemann-Pick disease: an atypical hemangioma enhancement pattern

Abstract

Introduction: Niemann-Pick disease (NPD) types A and B are lipid storage disorders. NPD type A is a fatal disorder of infancy. Type B is a non-neuronopathic form observed in children and adults. It is associated with enlargement of the liver, spleen, or both, and nodular splenomegaly may be detected with ultrasound.

Methods: A 21-year-old female was admitted to the Emergency Room with fever, pharyngitis, and left upper quadrant abdominal pain. Labwork revealed anemia, thrombocytopenia, increased levels of AST, ALT, GGT, AF, LDH, triglycerides, and total cholesterol and low levels of HDL-cholesterol. PCR blood assays for CMV and EBV were both negative. Chest X-ray was unremarkable. Transabdominal B-mode ultrasound (US) revealed splenomegaly (long axis: >22 cm), an irregular subcapsular hypoechoic lesion in the superior pole that was consistent with splenic infarction, and multiple round highly echogenic nodes measuring 1-5 cm in diameter. Contrast-enhanced ultrasonography (CEUS) was performed using SonoVue(®) (Bracco).

Results: The presence of a splenic infarction was confirmed. The nodular lesions showed arterial-phase enhancement with late parenchymal phase wash-out. (18)F-FDG-PET revealed splenic nodular uptake. Primary splenic lymphoma was suspected, and the patient underwent open splenectomy. The diagnosis was type B NPD with splenic hemangiomas.

Discussion: CEUS confirmed the diagnosis and extent of splenic infarction, but the nodular atypical enhancement pattern together with nodular (18)F-FDG-PET uptake was misleading, suggesting as it did lymphoproliferative involvement of the spleen.

Keywords: CEUS; Niemann–Pick disease; Nodular splenomegaly.

Figures

Fig. 1

(a) B-mode US: well-defined hyperechogenic nodule in the spleen measuring 4.7 cm in diameter (white arrow). (b) Macroscopically, the nodule appeared brownish and spongy (white arrowhead).

Fig. 2

(a) Late phase CEUS (3 min) showing splenic infarction(white arrow) and a close nodule (white arrowhead). (b) Macroscopic appearance of the splenic infarction (white arrow) and the spleen node (white arrowhead).

Fig. 3

CEUS performed after injection of a second SonoVue® bolus (2.4 ml). (a) Contrast medium enhancement at 18 s. (b) Contrast medium enhancement at 39 s. (c) Contrast medium enhancement at 2.02 min.

Fig. 4

18F-FDG-PET showing uptake in correspondence with the splenic nodules (standard uptake by the largest nodule: 5.5).

Fig. 5

The spleen measured 25 × 14 × 5 cm and weighed 1200 g. It contained an obvious subcapsular infarct in the superior pole (white arrow).

Fig. 6

Microscopical appearance of the splenic parenchyma. (a) Oil Red O stain for lipid droplets in macrophages (5×). (b) Bone marrow biopsy showing foam cells (PG-M1 ×5).

Fig. 7

(a) CD34 staining in the splenic parenchyma. (b) CD34 staining in the splenic nodes show vessels that are ectasic (compared with those of the normal parenchyma). These findings are consistent with hemangioma (5×).