A superficial, hard subcutaneous nodule in the upper outer quadrant of the female breast, resembling elephant skin, should be considered as a possible filarial nodule. What tests are needed for superficial hard subcutaneous nodules like elephantiasis in female breast? 2.Immunological examination has strong sensitivity and specificity. 1.Indirect fluorescent antibody test has a positive rate of 92.8% for filarial parasites and 99.1% for filarial parasites. 2.Enzyme-linked immunosorbent assay antibody positivity rate of filarial parasites and microfilariae positivity rate of about 95%. Microfilariae and eosinophils of mammary epithelial cells are often visible under the microscope as curled masses with unclear structure. 4.Breast lump biopsy The larvae of filarial worms or microfilariae are often found in the granulation tissue, which can clarify the diagnosis. 5.Breast lymphangiogram can be seen with larger input lymphatic orifice and smaller output orifice. Gross morphology: Filarial intramammary masses are mostly irregular nodules, 1-5 cm in diameter, with an average diameter of 2-3 cm. The masses may be solitary or multiple, with a soft texture in the early stage and a hard texture in the late stage. In the center of the mass, there were multiple small sacs filled with grayish yellow or gray-white cheese-like material, sometimes with jelly-like material and bleeding, and filarial stumps were visible in the blood. The cysts were surrounded by blood-filled granulation tissue and then outward by dense fibrous tissue. Microscopically, the lymphatic vessel walls were seen to be congested and edematous, with eosinophil and monocyte infiltration, thickening of the lymphatic vessel walls, and embolization of the lumen by agglutination of fibrin, lymphocytes, and eosinophils. Subsequently, granulomatous lymphangitis with dead worms as the core and eosinophilic abscesses were seen in the lymphatic vessel walls. Fragments of adult worms and microfilariae are seen in the abscess. Tuberculosis-like granulomas formed by epithelioid cells and multinucleated giant cells and fibroblasts were seen around the eosinophilic abscesses, which were surrounded by granulation tissue. In the later stage, the lesion is fibrotic and calcified, with complete occlusion of the lymphatic lumen and stagnation of lymphatic fluid. Small lymphatic vessels flex and dilate and rupture, and lymphatic fluid enters the tissue interstitial space. Locally, in the stagnation of lymphatic fluid, the stimulation of protein-containing lymphatic fluid causes the proliferation of connective tissue and the formation of a firm and coarse swollen elephantiasis, which is rarely seen in the breast.