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Make the Diagnosis: Cutaneous nodule

MedpageToday

Presentation

Case Findings: A 68-year-old farmer presents for evaluation of a painless, solitary nodule that rapidly developed on his left fourth finger 3 weeks ago.

  • There was no antecedent trauma and he denies joint pain, swelling, or altered range of motion.
  • He feels well otherwise, with no fevers or constitutional symptoms.


  • What is your diagnosis?

1382% Giant molluscum contagiosum

2625% Sporotrichosis

1132% Prurigo nodule

3974% Keratoacanthoma

801% Mycetoma

1255% Cutaneous metastasis

Learnings

Keratoacanthomas are neoplasms considered to be a sub-type of squamous cell carcinomas that develop rapidly as solitary, painless lesions on sun-exposed skin with a characteristic crateriform appearance. The lesions are almost always large nodules with a central keratin-filled cup, resembling a β€œvolcano” on the skin. Left untreated, some keratoacanthomas spontaneously involute and resolve leaving an atrophic scar; however, as keratoacanthomas are a type of squamous cell carcinoma, treatment is recommended. Patients will rarely present with multiple, eruptive keratoacanthomas, and keratoacanthomas have been described to arise within scars or sites of skin injury, including following attempted, incomplete removal of individual keratoacanthomas. Keratoacanthomas have been reported to occur in the setting of some medications, including new targeted therapies for metastatic melanoma (the BRAF-inhibitor class of drugs).

Management & Therapy Tips

  • Keratoacanthomas are sub-type of squamous cell cancer with a distinct clinical appearance, which develop rapidly and may self resolve.
  • As a type of squamous cell, most keratoacanthomas warrant treatment.
  • Surgical excision, intralesional chemotherapy (such as with methotrexate, 5-fluorouracil, or in some cases bleomycin), or other destructive modalities may be employed.
  • In patients with multiple, eruptive keratoacanthomas, consider evaluating for a potential trigger, including a new medication, although this is quite rare.
  • To learn more about the diagnosis and treatment for this and hundreds of other skin diseases, visit Derm101.com .

    Download our handy mobile app on your iPhone and iPad for our on-the-go diagnostic and therapeutic reference.

    Derm101 is the leading online reference source for physicians who diagnose and treat skin diseases and is now available on the Web and via mobile devices (in English and in Spanish).


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