PMC9056249_01
Pretreatment computed tomography of neck soft tissue with contrast, axial image shows right internal jugular vein compressed to a slit by a large heterogenous jugulo-digastric mass.
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Transient compression upon the right internal jugular vein and complete occlusion of the proximal internal jugular vein by the heterogenous mass were also noted (Figure 1).
Primary effusion lymphoma involving skeletal muscle. Hematoxylin and Eosin stain shows skeletal muscle (blue asterixes) infiltrated and replaced by large neoplastic plasmacytoid cells. All images at 400X magnification.
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Consequently, ultrasound-guided fine core needle biopsies of the 7 cm heterogenous mass stained by hematoxylin and eosin revealed tissue cores of the skeletal muscle infiltrated by sheets of large atypical plasmacytoid cells with predominantly vesicular chromatin, high nuclear to cytoplasmic ratio, variably conspicuous nucleoli, and scant to moderate cytoplasm (Figure 2).
(a) Neoplastic cells diffusely positive for MUM-1. (b) HHV8 immunohistochemical stain is diffusely positive in neoplastic cells, while (c) a subset of neoplastic cells are positive for Epstein Barr virus encoded RNA by in situ hybridization staining. (d, e) The neoplastic cells show strong lambda light chain restriction (e) compared to kappa (d) light chain by in situ hybridization staining. (f) The neoplastic cells demonstrate a high proliferation index (<90%) as measured by Ki67 immunohistochemical stain. All images at 400X magnification.
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On immunohistochemical staining, the neoplastic cells were strongly and diffusely positive for MUM-1, EMA, and HHV8 and weakly for CD45, while in situ hybridization staining also revealed diffuse and strong staining for EBV-encoded RNA and strong lambda light chain restriction (Figure 3).
Immediate post treatment fused PET/CT. Seven weeks post initial head and neck CT. Approximate similar level demonstrating total resolution of the previous right heterogenous mass and right internal jugular compression. No fluorodeoxyglucose (FDG) avid lymph nodes seen.
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Surprisingly, during the course of his HAART treatment, his right neck mass steadily resolved with eventual complete restoration of the right internal jugular vein patency as seen on consecutive staging PET scans (Figures 4 and 5).
Second post treatment fused PET/CT demonstrating some FDG avidity in bilateral level 2 nodes and left axillary nodes which are reactive. The treated right jugulo-digastric mass not active or enlarged as demonstrated in Figure 1.
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Surprisingly, during the course of his HAART treatment, his right neck mass steadily resolved with eventual complete restoration of the right internal jugular vein patency as seen on consecutive staging PET scans (Figures 4 and 5).