Differential Diagnosis for a Meaty Cyst with Bloody Discharge

• Single Most Likely Diagnosis
  • Necrotic or Infected Sebaceous Cyst: This condition is characterized by a cyst that becomes infected or necrotic, leading to a meaty appearance and potentially bloody discharge. The presence of a cyst with these symptoms strongly suggests a sebaceous cyst that has become compromised.
• Other Likely Diagnoses
  • Infected Epidermoid Cyst: Similar to a sebaceous cyst, an epidermoid cyst can become infected, leading to a meaty appearance and discharge. The distinction between the two often requires histological examination.
  • Pilonidal Cyst or Sinus: Although more commonly found in the natal cleft, pilonidal cysts can occur elsewhere and present with discharge, which may be bloody if the cyst becomes infected.
  • Furuncle or Carbuncle: A furuncle (boil) or carbuncle (a group of furuncles) can present as a meaty, inflamed nodule with purulent or bloody discharge, especially if it ruptures.
• Do Not Miss Diagnoses
  • Squamous Cell Carcinoma: Although less common, a squamous cell carcinoma can present as a rapidly growing, ulcerated lesion with bloody discharge. Missing this diagnosis could have severe consequences due to the potential for metastasis.
  • Basal Cell Carcinoma with Secondary Infection: The most common form of skin cancer, basal cell carcinoma, can rarely present with signs of infection or ulceration, including bloody discharge, if it becomes secondarily infected.
• Rare Diagnoses
  • Dermatofibrosarcoma Protuberans: A rare skin cancer that can present as a firm, painless nodule which may ulcerate and bleed. It's essential to consider this in the differential due to its potential for local destruction and rare metastasis.
  • Metastatic Disease to the Skin: Rarely, internal malignancies can metastasize to the skin, presenting as nodules or ulcers with discharge. This would be an unusual presentation but is crucial not to miss due to the implications for the patient's prognosis and treatment.