Differential Diagnosis for Enlarging Subcutaneous Masses on Abdominal Wall with a Normal CT Scan
- Single Most Likely Diagnosis
- Lipoma: A benign tumor composed of fat tissue, which can grow under the skin and may not be visible on a CT scan if it doesn't contain significant amounts of calcification or if the scan was not specifically focused on the subcutaneous tissue.
- Other Likely Diagnoses
- Sebaceous cysts: These are common, benign cysts that can grow under the skin and may appear as enlarging masses, especially if they become inflamed or infected.
- Hematomas or seromas: Collections of blood or fluid under the skin can form masses, especially after trauma or surgery, and might not be evident on a CT scan if they are small or not significantly different in density from surrounding tissues.
- Neurofibromas: Benign nerve sheath tumors that can present as subcutaneous masses, potentially part of neurofibromatosis type 1, though they might be more noticeable on an MRI than a CT scan.
- Do Not Miss Diagnoses
- Soft tissue sarcomas: Although rare, these malignant tumors can present as enlarging subcutaneous masses and would be critical to diagnose early for effective treatment. A normal CT scan does not rule out sarcomas, especially if the tumor is small or has a similar density to surrounding tissues.
- Metastatic disease: Rarely, metastases from internal malignancies can present as subcutaneous nodules, and missing this diagnosis could have significant implications for patient management and prognosis.
- Rare Diagnoses
- Dermatofibrosarcoma protuberans (DFSP): A rare skin cancer that can appear as a subcutaneous mass, often with a long history of slow growth.
- Erythema nodosum or other panniculitides: Inflammatory conditions of the subcutaneous fat that can cause nodular masses, though these typically have associated systemic symptoms or skin changes.
- Subcutaneous mycoses: Fungal infections of the subcutaneous tissue, which can cause masses, especially in immunocompromised patients or after travel to endemic areas.