An Unusual Diagnostic Journey of a Spontaneously Resolving Breast Mass: When Rare Entities Cause Concerning Presentations

This case report describes an atypical presentation of an enlarging breast mass over the course of 2.5 months in a 42-year-old African American woman, which initially raised suspicion for a serious condition but ultimately resolved spontaneously, emphasizing the importance of considering a broad differential diagnosis in complex breast pathologies. Her past medical history was significant for a similar mass in the same breast two years ago, which resolved spontaneously without medical intervention. Initial physical exam findings, including skin ulcerations and nipple retraction, raised suspicion for inflammatory breast cancer. The patient underwent a biopsy of the right breast and positive axillary lymph node. The biopsy revealed acute and chronic inflammation, granulation-type tissue, and focal granuloma with suppuration, but no evidence of malignancy. The discordance between the patient's physical exam findings and the biopsy results prompted the medical team to consider alternative diagnoses, such as idiopathic granulomatous mastitis and cat scratch disease. Due to the discrepancy, the patient was asked to return in one month for a repeat biopsy. However, upon her return, the breast mass and positive axillary lymph node had decreased in size significantly, with the ulcerated areas showing signs of healing. The medical team decided to forego the repeat biopsy and instead closely monitor the patient's condition. This case underscores the importance of considering a wide range of potential diagnoses, integrating clinical, radiological, and pathological findings, and adopting a multidisciplinary approach to ensure accurate diagnosis and appropriate management in complex clinical cases.