What is the likelihood of malignant melanoma in a 31-year-old female with a long-standing belly button mole that has recently changed, accompanied by palpable lymph nodes in the neck and elbow, night sweats, and gastrointestinal symptoms, given her history of health anxiety and irritable bowel syndrome (IBS)?

Differential Diagnosis

• Single Most Likely Diagnosis
  • Benign melanocytic nevus with reactive lymphadenitis: The patient's history of a stable mole for 13 years with recent minor changes and the presence of moveable, non-tender lymph nodes suggest a benign process. The lymph nodes may be reacting to the minor changes in the mole or another non-specific stimulus.
• Other Likely Diagnoses
  • Primary melanoma with lymph node metastasis: Although the patient's mole has been stable for a long time, any changes in a mole should be evaluated for melanoma, especially with the presence of lymphadenopathy.
  • Lymphadenitis or lymphoid hyperplasia: The patient's lymph nodes are moveable and non-tender, which could indicate a benign inflammatory or reactive process.
  • Gastrointestinal issues (e.g., irritable bowel syndrome (IBS), gastroesophageal reflux disease (GERDC)): The patient's history of IBS and anxiety, along with symptoms like fullness under the left ribs and changes in bowel movements, suggest that gastrointestinal issues may be contributing to her symptoms.
• Do Not Miss Diagnoses
  • Malignant melanoma with lymph node metastasis: Although the patient's history and physical examination suggest a low likelihood of melanoma, it is crucial to rule out this diagnosis due to its potential severity and impact on prognosis.
  • Lymphoma: The presence of multiple lymph nodes in different areas of the body, although moveable and non-tender, necessitates consideration of lymphoma, which can be deadly if missed.
  • Other malignancies (e.g., gastrointestinal, metastatic): The patient's symptoms of night sweats, fullness under the left ribs, and changes in bowel movements, although non-specific, should prompt an evaluation for other potential malignancies.
• Rare Diagnoses
  • Carney complex: A rare genetic disorder characterized by multiple skin and mucosal lesions, including melanocytic nevi, and an increased risk of various tumors.
  • Bannayan-Riley-Ruvalcaba syndrome: A rare genetic disorder characterized by multiple melanocytic nevi, intestinal polyps, and an increased risk of certain tumors.
  • Blue rubber bleb nevus syndrome: A rare condition characterized by multiple melanocytic nevi and gastrointestinal lesions.