Tonsillar lymphoma is the most common malignant tumor of Waldeyer's ring and belongs to the Non-Hodgkin Lymphoma (NHL) group — the most frequent subtype is Diffuse Large B-Cell Lymphoma (DLBCL, 50-80%). Waldeyer's ring is the most common site of extranodal NHL involvement (50%). It typically presents with unilateral tonsillar enlargement and appears on CT/MRI as a homogeneously enhancing solid mass. Unlike SCC, significant necrosis, ulceration, and cavitation are not expected. It demonstrates marked diffusion restriction on DWI due to high cellularity and high metabolic uptake on FDG-PET. Cervical lymphadenopathy is frequent and whole-body PET-CT is the standard investigation for staging.
Age Range
40-80
Peak Age
60
Gender
Male predominant
Prevalence
Uncommon
Tonsillar lymphoma results from malignant transformation of lymphoid tissue in the palatine tonsils. Waldeyer's ring (palatine tonsils, adenoid, lingual tonsil, tubal tonsils) contains mucosa-associated lymphoid tissue (MALT) and is continuously exposed to antigenic stimulation. This chronic immune activation creates a substrate for genetic mutations in lymphoid cells. In DLBCL, malignant transformation of germinal center B cells occurs — BCL2, BCL6, MYC translocations are common. Very dense packing of malignant lymphoid cells creates the homogeneous appearance of the tumor — homogeneous enhancement on CT and homogeneous signal on MRI reflect this. High cellularity manifests as marked diffusion restriction and low ADC on DWI. Unlike SCC, neovascularity in lymphoma is not disorganized and stroma is minimal — therefore necrosis and cavitation are rare. Metabolically, high glucose consumption explains intense uptake on FDG-PET. EBV association exists in some subtypes (especially in immunosuppressed patients).
The combination of a homogeneous solid mass in a unilateral tonsil with marked DWI restriction (low ADC) is the signature finding of tonsillar lymphoma. This combination reliably distinguishes from SCC (heterogeneous + higher ADC) and benign hypertrophy (no DWI restriction).
Contrast-enhanced CT shows a homogeneously enhancing solid mass in a unilateral palatine tonsil. The mass completely fills the tonsil or extends beyond tonsillar margins toward the oropharyngeal airway. No significant necrosis, cavitation, or calcification is present — this feature is the most important CT finding distinguishing lymphoma from SCC. The mass is of soft tissue density (~40-60 HU) and shows homogeneous increase after contrast. Accompanying cervical lymphadenopathy findings should be evaluated.
Report Sentence
A homogeneously enhancing solid mass is noted in the left palatine tonsil, consistent with tonsillar lymphoma; no necrosis or cavitation was detected.
Tonsillar lymphoma shows marked diffusion restriction on DWI — high signal at b=1000 s/mm² and low values on ADC map (<0.6-0.8×10⁻³ mm²/s). This finding indicates high cellularity and is critically important in distinguishing lymphoma from benign hypertrophy and SCC. ADC value is also used for prognosis and treatment response monitoring — post-treatment ADC increase indicates response.
Report Sentence
The left tonsillar mass demonstrates marked diffusion restriction on DWI with an ADC value of ... ×10⁻³ mm²/s; lymphoma is the primary differential diagnosis.
Tonsillar lymphoma (especially DLBCL) shows intense FDG uptake on FDG-PET/CT — SUVmax typically >10. Uptake is homogeneous with no decreased uptake corresponding to necrotic areas (differs from SCC). PET-CT is the standard investigation for staging (Ann Arbor), treatment response assessment (Deauville criteria), and recurrence monitoring. Waldeyer's ring + cervical + distant nodal involvement patterns are evaluated.
Report Sentence
Intense FDG uptake is noted in the left palatine tonsillar mass (SUVmax: ...); consistent with lymphoma.
On MRI T2-weighted sequences, tonsillar lymphoma shows isointense or mildly hyperintense homogeneous signal. The high cellularity of lymphoma shortens T2 time — therefore marked T2 hyperintensity is not expected. Signal remains homogeneous if there is no internal necrosis or cystic change. This feature distinguishes from SCC (more heterogeneous T2 signal) and abscess (high T2 signal).
Report Sentence
The left tonsillar mass shows isointense to mildly hyperintense homogeneous signal on T2; no internal necrosis or cystic change was detected.
On intraoral or transcervical US, tonsillar lymphoma appears as a hypoechoic solid mass. The mass shows homogeneous echo pattern with no significant internal echogenicity (necrosis/calcification). Doppler shows increased vascularity. US is particularly useful in evaluating accompanying cervical LAP — lymphoma LAP appears as round, homogeneous, hypoechoic nodes with hilum loss.
Report Sentence
A hypoechoic solid mass is noted in the left tonsil with increased Doppler vascularity; accompanying bilateral cervical LAP is present.
Criteria
Most common subtype (50-80%), aggressive, CD20+
Distinct Features
Intense FDG uptake, good response to R-CHOP, rapid growth
Criteria
Indolent, slow growth, nodular pattern
Distinct Features
Lower FDG uptake, watch-and-wait strategy may be appropriate
Criteria
From mucosa-associated lymphoid tissue, indolent
Distinct Features
Slow course, local disease, good response to radiotherapy
Distinguishing Feature
SCC heterogeneous, necrosis common, ulceration and invasive margins; lymphoma homogeneous, minimal necrosis
Distinguishing Feature
Hypertrophy bilateral symmetric, no DWI restriction; lymphoma unilateral, marked DWI restriction
Distinguishing Feature
Abscess rim-enhancing hypodense collection, acute clinical; lymphoma solid homogeneous mass, subacute/chronic
Urgency
urgentManagement
medicalBiopsy
NeededFollow-up
specialist-referralBiopsy (preferably excisional/incisional) is mandatory in suspected tonsillar lymphoma — FNA is insufficient for lymphoma subtyping. Staging is performed with FDG-PET/CT. DLBCL responds well to R-CHOP chemotherapy; additional radiotherapy may be given for localized disease. 5-year survival is 70-80% for early-stage disease.
Tonsillar lymphoma has a good prognosis with early diagnosis and staging. Biopsy (preferably excisional) is required for diagnosis. FDG-PET/CT is the standard investigation for staging and treatment response assessment. DLBCL responds well to R-CHOP chemotherapy.