Differential Diagnosis for a Lump or Soft Tissue Mass
Single Most Likely Diagnosis
- Lipoma: This is a common, benign tumor composed of fat tissue. It is the most likely diagnosis for a soft tissue mass due to its high prevalence and the fact that it often presents as a palpable, soft lump under the skin.
Other Likely Diagnoses
- Cyst: Fluid-filled sacs that can form under the skin, often due to a blocked oil gland or hair follicle. They can feel like soft lumps and are relatively common.
- Abscess: A collection of pus that has built up within the tissue of the body, indicating a local infection. It can present as a painful, soft lump.
- Hematoma: A collection of blood outside of blood vessels, which can occur due to injury and may feel like a soft lump.
- Fibroma: A benign tumor of fibrous or connective tissue. It can present as a firm or soft lump, depending on its composition.
Do Not Miss Diagnoses
- Soft Tissue Sarcoma: Although rare, this malignant tumor of the soft tissue (such as muscle, fat, or blood vessels) is critical to diagnose early due to its potential for aggressive behavior and poor prognosis if not treated promptly.
- Metastatic Disease: In patients with a history of cancer, a new soft tissue mass could represent a metastasis, which would significantly alter management and prognosis.
- Infected or Inflammatory Mass: Conditions like a infected cyst, cellulitis, or an inflammatory pseudotumor can mimic a soft tissue tumor but require different management.
Rare Diagnoses
- Neurofibroma: A benign tumor of the nerve tissue, which can occur in isolation or as part of neurofibromatosis type 1. It presents as a soft, sometimes painful lump.
- Desmoid Tumor (Aggressive Fibromatosis): A rare, benign but locally aggressive tumor of fibrous tissue that can grow to significant sizes and cause symptoms due to local invasion.
- Myxoma: A rare, benign tumor of soft tissue that can occur in various parts of the body, including the skin and subcutaneous tissue. It is characterized by a soft, gelatinous texture.