case_images: PMC9108331_01
case_images: Nuclear MRI examination of the patient. (A-H) MRI of the upper abdomen shows an abnormal signal of the spleen. (A-C) The transverse position of the MRI shows that the spleen is enlarged. A mass occupying shadow, approximately 8.4 cm x 5.7 cm x 6.3 cm in size, is seen in the lower part of the spleen, with clear boundary and a slightly low signal on T1WI and slightly high signal on T2WI. Uneven signal is observed in the spleen, with small cystic cavities and a longer T2 signal. (D, E) MRI shows progressive enhancement patterns. (F) Spindle-shaped abnormal signal can be seen under the capsule of the spleen above the lesion, with a smooth edge, septa inside, mixed signals, and fluid-fluid level in the chamber, indicative of a hematoma under the capsule of the spleen. (G, H) A nodular T1/T2 hypointense shadow, approximately 3.3 cm x 3.6 cm in size, was seen in the lower part of the lesion compressing the left kidney nearby. T1WI, T1-weighted imaging; T2WI, T2-weighted imaging.
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case_images: A slightly low signal was observed in T1-weighted imaging (T1WI) and a slightly high signal in T2-weighted imaging (T2WI), and the signals were uneven ( Figures 1A-E ). T2 signal were observed in association with the lesion below. The size of the mass was approximately 3.3 cm x 3.6 cm, and it compressed the adjacent left kidney. The possibility of splenic hemangioma was considered, with calcification below the lesion and splenic subcapsular hematoma formation (absorption phase) ( Figures 1F-H ).
case_images: (A-C) Digital subtraction angiography (DSA) examination of the patient. DSA images show splenic embolism in the patient.
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case_images: Digital subtraction angiography (DSA), splenic arteriography, and embolization were performed 4 days after the onset of symptoms, with the consent of the patient's family ( Figure 2 ).
case_images: CT examination of the patient. (A-F) CT of the upper abdomen shows abnormal density of the spleen, and the transverse position of the CT image shows pleural effusion in the left thoracic cavity. (C) In the spleen, there is a mass of mixed density shadow with unclear margin, with a maximum cross-sectional area of approximately 9.2 cm x 6.1 cm. (D, E) The left renal margin is rough, and the density of the spindle-shaped shadow is slightly higher under the left renal capsule. (F) The coronal position of the CT image shows a flake-like high-density shadow in the lower margin of the spleen.
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case_images: CT showed a bulk-like mixed density shadow in the spleen with poorly defined margins, a maximum cross-sectional size of approximately 9.2 cm x 6.1 cm, and hemorrhage ( Figure 3C ). A flake-like high-density shadow was seen in the lower margin of the spleen, which was considered to be a change after embolization ( Figures 3D, F ). Moreover, a spindle-shaped, slightly high-density shadow with a rough margin under the left renal capsule was observed, which was considered to be a small subcapsular hematoma of the left kidney ( Figure 3E ).
case_images: Pathological examination and immunohistochemistry (IHC) of the patient. (A) H&E, x100, the tumor cells grew diffusely in sheet form, with parts arranged in a slightly weave-like manner, in which multinucleated giant cells were scattered and small areas of necrosis were seen. (B) H&E, x200, osteoclast-like multinucleated giant cells were scattered in tumor cells. (C) H&E, x400, lace- or grid-like tumor osteogenesis is observed. (D) beta-Catenin (++), x200, the tumor cell membrane in beta-catenin was positive. (E) SMA (-),x200; (F) CD99 (-), x200; (G) CD68 (+), x200; positive expression of cytoplasmic CD68 was found in osteoclast-like giant cells. (H) BCL-2 (++), x200; (I) Ki-67 (50%+), x200; the proliferation index of Ki-67 was 50%. (J) SATB-2 (++), x200; SATB-2 showed diffuse positive expression in the tumor nucleus. (K) P16 (++), x200; P16 showed diffuse positive expression in the tumor; (L) MDM-2 (+), x200; MDM-2 was positive in parts of the tumor cells. According to the above description, the patient was diagnosed with primary extraskeletal osteosarcoma.
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case_images: Another free mass of 5 cm x 4 cm x 3 cm with partial calcification was observed, as well as a free clot of 18 cm x 10 cm x 4 cm with partial graying that showed a splenic soft tissue tumor ( Figures 4A-C ). Under low magnification, the tumor cells grew in diffuse sheets with a slightly woven arrangement in some areas, scattered multinucleated giant cells, and small focal necrosis ( Figure 4A ). Under medium magnification, scattered osteoblast-like multinucleated giant cells were observed among tumor cells ( Figure 4B ). Under high magnification, the tumor cells were cytoplasm-rich and round/oval in shape, with many nuclear schizophrenic images and pink-stained bone-like stroma formation (tumor osteogenesis), which was lace- or grid-like, with calcium salt deposits (purple-blue) in some areas ( Figure 4C ). The remaining indicators, CD31, CD34, F8, s-100, and desmin, were negatively expressed ( Figures 4D-L ).