What is the approach for a patient presenting with a painless parotid mass, started 2 days ago, with computed tomography (CT) findings of an enlarged parotid gland and lymph nodes?

Approach to Painless Parotid Mass with Enlarged Lymph Nodes on CT

MRI with and without IV contrast is the preferred initial imaging modality for comprehensive evaluation of a painless parotid mass with lymphadenopathy, as it provides detailed information about the extent of the mass, local invasion, and possible extension into surrounding structures. 1

Initial Assessment

History

• Duration of symptoms (recent onset - 2 days in this case) 1
• Pain (absence of pain may suggest certain pathologies like lymphoma) 2, 3
• Associated symptoms:
  • Facial weakness (suggests malignancy or nerve involvement) 1
  • Fever, weight loss, night sweats (suggests lymphoma or infection) 4
  • History of autoimmune disorders (increases risk of lymphoma) 2
  • Recent infections or trauma 1, 5

Physical Examination

• Careful palpation of the mass:
  • Size, consistency, mobility, and borders 1
  • Multiple ipsilateral or bilateral lumps (seen in 30% of parotid lymphomas) 3
• Complete head and neck examination:
  • Facial nerve function assessment (VII cranial nerve) 1
  • Examination of all cervical lymph node chains 1
  • Intraoral examination for any extension or additional masses 1
• Skin examination over the mass (erythema, warmth, fluctuance) 2

Diagnostic Workup

Imaging

• MRI with and without IV contrast is the preferred initial imaging modality 1
  • Provides comprehensive information about extent, local invasion, and possible extension
  • T2-hypointensity, intratumoral cystic components, and abnormal diffusion coefficient values suggest malignancy
• CT with IV contrast can be used when MRI is contraindicated 1
  • Already performed in this case, showing enlarged parotid with lymph nodes
• Ultrasound can be useful for initial assessment 1
  • Helps distinguish parotid versus extraparotid masses
  • Limitations in visualizing deep lobe lesions

Tissue Diagnosis

• Fine needle aspiration biopsy (FNAB) is essential to distinguish between inflammatory, infectious, and malignant causes 1, 5
  • May be non-diagnostic in certain conditions like lymphoma 6
• Core needle biopsy if FNAB is inadequate 1
• Consider incisional biopsy in suspected lymphoma cases 6

Differential Diagnosis for Painless Parotid Mass with Lymphadenopathy

• Malignant neoplasms:

  • Lymphoma (particularly when presenting with painless mass and lymphadenopathy) 2, 6, 3
  • Metastatic disease (consider primary sites like skin or mucosal surfaces) 4
  • Primary salivary gland malignancies 1

• Benign neoplasms:

  • Pleomorphic adenoma 1
  • Warthin's tumor 7
  • Lymphadenoma 7

• Non-neoplastic conditions:

  • Castleman's disease (rare in parotid) 8
  • Sialadenitis with reactive lymphadenopathy 5
  • Intraparotid lymph node hyperplasia 1, 5

Management Algorithm

1. Initial Imaging: MRI with and without IV contrast (if not already done) 1

2. Tissue Diagnosis:

   • FNAB as first-line diagnostic procedure 1
   • If FNAB is non-diagnostic and lymphoma is suspected, consider biopsy of associated lymph nodes before parotid surgery 3
   • Core needle biopsy or incisional biopsy if FNAB inconclusive 1, 6

3. Treatment Based on Diagnosis:

   • For confirmed malignancy:
     • Surgical excision for salivary gland malignancies 1
     • Chemotherapy ± radiation for lymphoma (avoiding unnecessary parotidectomy) 2, 6
   • For benign neoplasms:
     • Surgical excision with appropriate margins 1
   • For inflammatory conditions:
     • Medical management with appropriate anti-inflammatory or antimicrobial therapy 5

Important Considerations and Pitfalls

• Rapid onset (2 days) is unusual for most neoplasms and may suggest an inflammatory or infectious process, but does not rule out malignancy 1, 5

• Do not rely solely on imaging to determine if a parotid lesion is benign or malignant; histologic confirmation is required 1

• Avoid unnecessary parotidectomy in suspected lymphoma cases; biopsy of associated lymph nodes may provide diagnosis without risking facial nerve injury 6, 3

• Consider lymphoma when a patient presents with a painless parotid mass and associated lymphadenopathy, especially with multiple ipsilateral or bilateral lumps 2, 3

• Facial nerve preservation is critical in surgical management unless there is preoperative dysfunction or direct tumor invasion 1