Axillary Lymph Nodes in Breast Filariasis
Yes, axillary lymph nodes can become palpable in filariasis affecting the breast, and this presentation can mimic breast carcinoma with metastatic lymphadenopathy. 1
Clinical Presentation and Pathophysiology
Filariasis involving the breast and axillary region presents with distinct characteristics that clinicians must recognize:
Adult filarial worms reside in lymphatics and lymph nodes, causing dilatation of lymphatics and thickening of vessel walls, which leads to progressive lymphatic damage and palpable adenopathy 2
Axillary lymphadenovarix (grossly dilated lymphatics forming matted lymph node masses in the axilla) represents a rare but documented presentation of Bancroftian filariasis 1
The clinical presentation can include multiple matted lymph nodes with cystic areas forming large masses in the axilla, making differentiation from malignancy challenging on physical examination alone 1
Filariasis of the breast with axillary lymphadenopathy and lymphedema has been reported to mimic breast carcinoma clinically 3
Diagnostic Approach
When encountering palpable axillary lymphadenopathy in endemic regions, follow this algorithmic approach:
Initial Imaging
Axillary ultrasound is the primary modality of choice to evaluate node morphology and determine if masses are solid or cystic 4
Ultrasound may reveal grossly dilated lymphatics in cases of lymphadenovarix, though the filarial dance sign (visualization of live adult worms) may be absent 1
Diagnostic mammography should complement axillary ultrasound to evaluate for potential breast primary lesions and differentiate from breast carcinoma 4
Definitive Diagnosis
Fine needle aspiration cytology (FNAC) from dilated lymphatics and solid areas can demonstrate microfilariae in a background of reactive lymphoid cells 1
Ultrasound-guided core needle biopsy provides definitive diagnosis with 98-100% specificity and should be performed for suspicious nodes 4
Peripheral blood smears should be examined for microfilaremia, which is often accompanied by significant eosinophilia 1
Excisional biopsy is both diagnostic and therapeutic in cases of subcutaneous dirofilariasis presenting as breast or axillary nodules 5
Critical Differential Diagnosis Considerations
The differential diagnosis of palpable axillary lymphadenopathy in endemic regions includes:
Metastatic breast cancer remains the most common malignant cause when cancer is identified in axillary nodes, even in endemic areas 6, 7
Reactive lymphadenopathy from infections is the most common benign etiology according to the American College of Radiology 7
Microfilariae have been observed as coincidental findings in metastatic axillary nodes from breast carcinoma, making tissue diagnosis essential 3
Common Pitfalls and How to Avoid Them
Never rely on physical examination alone, as filariasis with axillary lymphadenopathy can clinically mimic breast carcinoma with metastatic disease 3
Do not assume benign etiology based solely on endemic location—tissue diagnosis is mandatory to exclude malignancy, as both conditions can coexist 3
Always examine peripheral blood smears for microfilariae and eosinophilia when filariasis is in the differential diagnosis 1
Consider filariasis in the differential diagnosis of any patient presenting with breast or axillary nodules in endemic regions (tropical and subtropical countries including India, South America, Central Africa, Pacific, and Caribbean) 2, 8, 5