Sinonasal plasmablastic lymphoma

Case contributed by Jeffrey Hocking
Diagnosis certain


Headache, diplopia, vertigo. Background of HIV.

Patient Data

Age: 65 years
Gender: Male

Large homogeneously enhancing solid mass centered within the midline paranasal sinuses, measuring 51 x 36 x 47mm (AP x TR x CC).

  • Adjacent osseous bowing and erosion of the sphenoid sinuses and ethmoidal air cells.
  • Posterior margin of the nasal septum has been completely eroded.
  • Expansion of the right maxillary antrum with extension of the mass into the maxillary sinus, and adjacent inspissated secretions due to obstruction.
  • The mass bulges into the medial extraconal fat of the right orbit with thinning of the adjacent lamina papyracea and proptosis, and lateral bulging of the medial rectus muscle. Moderate narrowing of the right optic canal and orbital apex with compression of the optic nerve sheath complex, and mild narrowing on the left.
  • Inspissated secretions within the frontal sinuses bilaterally.
  • Erosion of the anterior margin of the sella turcica, and superior extent of the clivus, with focal dehiscence of the posterior clival cortex. Dehiscence of the medial walls of the carotid canals bilaterally.
  • The pituitary cannot be reliably identified as separate to the mass. Infundibulum is midline and normal thickness. No compression of the optic chiasm.
  • Bulging of the floor of the anterior cranial fossa, but no evidence of invasion into the brain. Near complete occlusion of the choanae.

Contrast not given due to poor renal function.

Large mass within the nasal passages and sphenoid sinus, expanding into the right orbit and right maxillary sinus, with erosion of the nasal septum and clivus. Low signal on T1 and T2 images with diffusion restriction. No areas of cystic change or necrosis.

While there is bony erosion of the cribriform plate, planum sphenoidale, floor of the pituitary fossa and clivus, no definite extension of tumor through the dura and no involvement of the brain on the imaging available.

Nuclear medicine

Avid uptake in sinonasal mass


Sections show a diffuse infiltrate of atypical blast like large cells showing focal plasmacytoid differentiation. The cells are positive for CD138, CD45, CD79a, CD30, EMA, c-myc (50%), CD56, MUM1(strong) and EBER but negative for CD2, CD3, CD20, CD5, CD23, TdT, BCL6, CD15, p16, PAX5, p63, ALK, MNF116, S100, SOX10, synaptophysin and cyclin D1. The cells show lambda light chain restriction. Ki-67 shows a proliferation index of 90%.

The overall features are in keeping with plasmablastic lymphoma.

Case Discussion

Plasmablastic lymphoma is a rare DLBCL that more commonly occurs in HIV / immunocompromised patients. As with other lymphomas it is iso-intense on both T1 and T2 imaging.

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