Benign lymphoepithelial lesions (BLL or BLEL), also misleadingly known as AIDS-related parotid cysts (ARPC), are mixed solid and cystic lesions that enlarge the parotid glands, and are usually associated with cervical lymph node enlargement, and nasopharyngeal lymphofollicular hyperplasia.
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Despite their aforementioned alternative name, BLL are seen usually in HIV positive patients without AIDS, and are not an AIDS defining illness. It is relatively common in the HIV population, with 5% of patients eventually developing BLL.
Thought to arise from dilatation of intraglandular ducts from obstruction due to lymphoid hypertrophy. They are bilateral in ~20% of cases.
- well circumscribed cystic spaces
- may demonstrate thin rim enhancement on post contrast MRI
- ultrasound demonstrates these 'cystic' lesions to actually have multiple small septations, and commonly also small mural nodules (40%)
- a vascular pedicle may be seen entering the cystic region
BLLs are usually seen associated with other sites of lymphoid hyperplasia 4, including:
- prominent nasopharyngeal adenoidal tissue: seen in 35% of HIV positive patients 4
- posterior triangle lymphadenopathy
- abnormal bone marrow signal
On imaging consider
- first branchial cleft cyst
- Warthin tumour
- Sjogren syndrome
- necrotic intraparotid lymph nodes
- 1. Martinoli C, Pretolesi F, Del bono V et-al. Benign lymphoepithelial parotid lesions in HIV-positive patients: spectrum of findings at gray-scale and Doppler sonography. AJR Am J Roentgenol. 1995;165 (4): 975-9. AJR Am J Roentgenol (abstract) - Pubmed citation
- 2. Bialek EJ, Jakubowski W, Zajkowski P et-al. US of the major salivary glands: anatomy and spatial relationships, pathologic conditions, and pitfalls. Radiographics. 26 (3): 745-63. doi:10.1148/rg.263055024 - Pubmed citation
- 3. Holliday RA, Cohen WA, Schinella RA et-al. Benign lymphoepithelial parotid cysts and hyperplastic cervical adenopathy in AIDS-risk patients: a new CT appearance. Radiology. 1988;168 (2): 439-41. Radiology (abstract) - Pubmed citation
- 4. Yousem DM, Loevner LA, Tobey JD et-al. Adenoidal width and HIV factors. AJNR Am J Neuroradiol. 1997;18 (9): 1721-5. AJNR Am J Neuroradiol (abstract) - Pubmed citation