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Difficulty: MediumRheumatology and Immunology

A 58-year-old woman comes to the clinic reporting a 6-week history of a progressively enlarging mass on the right side of her face. She also reports soaking night sweats and a 4-kg (8.8-lb) unintentional weight loss over the past 2 months. She has a 12-year history of primary Sjögren syndrome, which is managed with artificial tears and pilocarpine. Physical examination reveals a 4-cm, firm, non-tender, immobile mass in the right parotid region. Right-sided cervical lymphadenopathy is also present. Her past parotid enlargements associated with her autoimmune disease were bilateral, soft, and fluctuated in size. Laboratory studies show an elevated lactate dehydrogenase (LDH) level. Which of the following is the most likely etiology of this patient's new symptoms?

  1. B-cell non-Hodgkin lymphomaAnswer
  2. B
    Pleomorphic adenoma
  3. C
    Suppurative parotitis
  4. D
    Sialolithiasis
  5. E
    Exacerbation of Sjögren syndrome

Answer

B-cell non-Hodgkin lymphoma
The correct answer is B-cell non-Hodgkin lymphoma. Patients with primary Sjögren syndrome have a substantially increased risk (estimated at 15 to 44 times that of the general population) of developing B-cell non-Hodgkin lymphoma, most commonly mucosa-associated lymphoid tissue (MALT) lymphoma or diffuse large B-cell lymphoma. The classic presentation of this malignant transformation is a new, progressively enlarging, unilateral, firm, and non-tender mass in a major salivary gland (often the parotid), accompanied by regional lymphadenopathy and systemic B-symptoms such as night sweats and unintentional weight loss. An elevated LDH level further supports a highly proliferative malignant process. While benign, bilateral, soft parotid enlargement is a common baseline feature of Sjögren syndrome, a unilateral, firm, fixed mass represents a critical red flag for lymphoma.

Step-by-Step Solution

1
Analyze the patient's baseline medical history.
The patient has a 12-year history of primary Sjögren syndrome.
Establishing the chronic underlying disease helps identify associated long-term complications and distinguishes them from new, unrelated conditions.
2
Identify the key clinical features of the current presentation.
The patient has a new-onset, firm, immobile, unilateral parotid mass accompanied by cervical lymphadenopathy, systemic B-symptoms (night sweats, weight loss), and elevated LDH.
Differentiating these progressive, alarming features from her baseline chronic, bilateral, soft parotid swelling is critical.
3
Correlate the new clinical findings with the underlying disease risk profile.
Sjögren syndrome is strongly associated with an increased risk of developing B-cell non-Hodgkin lymphoma, which perfectly matches the presentation of a malignant salivary mass and systemic symptoms.
Recognizing this specific epidemiological association leads directly to the correct malignant etiology.

Key Concept

Patients with primary Sjögren syndrome have a markedly increased risk (up to 44-fold) of developing B-cell non-Hodgkin lymphoma. A new, progressively enlarging, unilateral, firm parotid mass accompanied by B-symptoms should immediately raise suspicion for malignant transformation.
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Topics

Rheumatology and Immunology

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