Differential Diagnosis
- Single most likely diagnosis
- Seborrheic keratosis or benign skin growth: The presence of a long-standing "ball" in the belly button with recent changes in color and the ability to pick off darker spots suggests a benign skin growth. The fact that it has been present for 13 years with minimal change reduces the likelihood of a malignant process.
- Other Likely diagnoses
- Neurodermatitis or skin irritation: The patient's extreme health anxiety may contribute to excessive picking or scratching of the skin, leading to irritation and post-inflammatory hyperpigmentation, which could explain the brown spots.
- Folliculitis or infected ingrown hair: The location in the belly button, an area prone to moisture and friction, increases the risk of folliculitis or infected ingrown hairs, which could cause lymphadenopathy.
- Idiopathic lymphadenopathy: The presence of palpable lymph nodes without other symptoms could be idiopathic, especially given the patient's anxiety, which may lead to increased awareness and reporting of bodily sensations.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Malignant melanoma: Although the patient's symptoms and history are not highly suggestive of melanoma, it is essential to consider this diagnosis due to its potential severity and the patient's conviction. A thorough examination and potential biopsy are necessary to rule out melanoma.
- Lymphoma: Although less likely, lymphoma could present with lymphadenopathy, and a thorough evaluation, including imaging and potentially a lymph node biopsy, may be necessary to rule out this diagnosis.
- Rare diagnoses
- Dermatofibroma: A rare, benign skin growth that could present as a firm, pigmented nodule, potentially explaining the "ball" in the belly button.
- Mastocytosis: A rare condition characterized by excessive mast cell accumulation, which could lead to skin lesions and lymphadenopathy, although this would be an unusual presentation.