Differential Diagnosis for Small Mobile Nodules Scattered Along the Arms and Trunk
- Single Most Likely Diagnosis
- Lipomas: These are benign tumors composed of fat tissue and are very common. They are often found just beneath the skin and can be felt as soft, mobile lumps. Their presence on the arms and trunk, as described, fits well with the typical presentation of lipomas.
- Other Likely Diagnoses
- Cysts (Epidermoid or Sebaceous): These can present as mobile, firm nodules under the skin. They are benign and can occur anywhere on the body, including the arms and trunk.
- Neurofibromas: These are benign nerve sheath tumors that can be mobile and are often found in patients with neurofibromatosis type 1. However, they can also occur sporadically.
- Dermatofibromas: These are small, hard bumps that can develop on the skin, often as a result of minor injury, and can feel like mobile nodules.
- Do Not Miss Diagnoses
- Metastatic Disease: Although less common, it's crucial not to miss the possibility of metastatic cancer presenting as skin nodules. Certain types of cancer, like breast, lung, or melanoma, can metastasize to the skin.
- Lymphoma (Cutaneous T-Cell Lymphoma): This can present with skin lesions or nodules, and while less likely, it's a critical diagnosis not to overlook due to its potential severity.
- Rare Diagnoses
- Erdheim-Chester Disease: A rare form of histiocytosis that can present with skin xanthomas or nodules, among other systemic symptoms.
- Rheumatoid Nodules: Associated with rheumatoid arthritis, these can be found on the skin, particularly over bony prominences, but are less likely to be described as small and mobile.
- Sarcoidosis: This condition can cause skin nodules, but they are often accompanied by other systemic symptoms such as lung or eye involvement.