Fig. 1.

Case 1. 11-month-old female infant presented with intermittent fever.

A. Contrast-enhanced CT of abdomen shows splenomegaly (about 14 cm) with multifocal low density lesions in spleen (arrows). Soft tissue density lesions are seen in porta hepatis (arrowheads). B. Contrast-enhanced CT of chest shows nodular enlargement of thymus with bilateral pleural effusions. C. Typical histology of Langerhans cell sarcoma with malignant cytological features, such as atypia, hyperchromatic nuclei (H&E, × 400), and prominent nucleoli. D, E. Cells are immunopositive for CD1a (× 400) and S-100 (× 400). F. At 16 months after chemotherapy, follow-up MRI of orbit (fat-suppressed T2-weighted image) shows well-enhancing soft tissue mass extending from anterior skull base (including sphenoid wing and infratemporal fossa) to lateral aspect of right orbit and frontal area (arrow). G. Follow-up CT of orbit shows associated adjacent bony destruction with irregular sharp margin (arrow). Osteolytic lesions involving anterior skull base to lateral aspect of left orbit are also noted (arrowheads).