Recognizing Amelanotic Melanoma In The Lower Extremity

Author(s): 
Bryan C. Markinson, DPM, FASPD

Case Study One: When Drainage And Granulation Tissue Persist After A Nail Avulsion

A 74-year-old female presented to the office of a colleague with medial nail fold swelling, granulation tissue and drainage of the right hallux. The physician diagnosed a paronychia and performed a straight back nail avulsion with local anesthesia. After drainage and granulation tissue persisted, and the physician ruled out a retained nail fragment, a biopsy revealed deeply invasive melanoma. The patient received a referral for definitive treatment. The patient underwent positron emission tomography (PET) scanning, which was negative.

   After amputation of the hallux to the level of the MPJ and sentinel lymph node biopsy (which was ultimately negative), she received interferon treatment. She succumbed in four years with lung metastases.

Case Study Two: Can A Damaged Toenail Signal Invasive Melanoma?

A 66-year-old female stated that her nail fell off after wearing a tight shoe (see photo at left). Being diabetic, she received treatment for infection for three weeks. Her DPM recommended biopsy due to non-resolution of granulation tissue in the nail bed but she delayed having a biopsy. After three months, she relented and the physician performed two punch biopsies through the nail bed.

   After two punches through the nail bed, the diagnosis was amelanotic nodular melanoma. The patient underwent amputation to the level of the MPJ and sentinel node biopsy. Preoperative PET scanning was negative. The depth of the lesion on microscopic examination was 11 mm and invasive to bone. It is important to note that immediately before losing the nail, the patient noted that the nail’s appearance was exactly like that of the adjacent, normal third toenail.

   After undergoing an amputation and negative sentinel node biopsy, the patient had interferon therapy. As of this writing, there is no evidence of disease.

Case Study Three: Was A Toenail Lesion The Result Of A Hiking Boot That Was Too Snug?

A 70-year-old male patient stated unequivocally that his third toenail lesion occurred on a recent hiking trip three weeks prior and that at the beginning of the trip, the nail unit was identical in appearance to the adjacent clear nail (see photo at right). He attributed the lesion to rubbing from a hiking boot. He then saw his regular DPM, who referred him for a workup of this lesion.

   A biopsy eventually revealed a level IV invasive melanoma. The patient was lost to follow-up as care continued at another institution.

Case Study Four: When A Patient Develops Toenail Lysis After A Pedicure

A 65-year-old female patient went for her regular pedicure in August 2009 and states she felt a sharp pain in the right hallux when the pedicurist used a certain instrument (see photos at left). She did not bleed. She developed toenail lysis centrally two weeks later and saw a DPM, who assumed infection based on the history. Treatment continued until the patient sought another opinion in late January 2010.

   The patient received a referral to me. I performed a biopsy on the initial visit on February 15, 2010. Histology revealed nodular amelanotic melanoma of at least 2.7 mm in depth with many evident mitoses.

   The patient then underwent amputation to the level of the MPJ and a sentinel lymph node biopsy. This revealed a very large sentinel node that was positive for melanoma. Subsequent lymph node dissection of the groin revealed more positive nodes, leading to a very grim prognosis.

   As of this writing, the patient has severe lymphedema of the right leg due to the complete groin dissection and is getting ready to start chemotherapy.

Comments

The literature states that melanoma in the foot is rare for a specific reason: feet have been neglected by "regular" doctors. Since podiatry has shifted into the surgical realm, I suspect that the incidence of melanoma in the foot will rise.

Be prepared to be removed from the course of treatment if a malignancy is detected. No matter how credentialed a podiatrist you might be, there is no place in the regimen of care rendered to the melanoma patient but for reassurance.

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