Diagnosis: Acral lentiginous melanoma
A 55-year-old female with dark skin presented with an asymmetric, pigmented patch on the plantar surface of her foot that had been enlarging over the past year. Initial evaluation revealed irregular borders and variegated pigmentation, raising concern for a malignant process, particularly given her skin type and the location of the lesion.
A 55-year-old African American female presented with a pigmented lesion on the plantar aspect of her right foot, which she had first noticed approximately one year ago. The lesion was asymptomatic but had gradually enlarged, prompting her to seek evaluation. On examination, the lesion measured approximately 2.5 cm, with irregular borders, variegated pigmentation ranging from light brown to black, and asymmetry in shape. There was no associated lymphadenopathy.Location: Primarily on the plantar surface of the foot.Duration: Present for approximately one year.Characteristics: Asymmetrical, irregularly bordered, and multi-colored.Size: Approximately 2.5 cm in diameter.Symptoms: Asymptomatic, no itching or bleeding.
The patient reported that the lesion began as a small brown spot that gradually enlarged. She denied any history of trauma to the area or exposure to UV radiation, as she primarily worked indoors. There was no significant family history of skin cancer. The patient had a history of hypertension and was on lisinopril. Socially, she was a non-smoker and denied alcohol use. No prior treatments were attempted for the lesion.Onset: Small brown spot that enlarged over one year.Triggers: No known trauma or UV exposure.Past medical history: Hypertension, controlled with medication.Family history: No known skin cancer.Social history: Non-smoker, no alcohol use.
Acute / First-Line ManagementWide local excision of the melanoma with clear margins (typically 1-2 cm) is the standard initial treatment.Sentinel lymph node biopsy (SLNB) may be considered for staging and further management, particularly if the lesion is >1 mm in thickness.Workup and Diagnostic ConfirmationHistopathological examination of the excised tissue is essential for diagnosis confirmation.Immunohistochemical staining can be performed to assess for melanoma-specific markers such as HMB-45, S-100, and Melan-A.Further imaging studies (e.g., chest X-ray, CT scan) may be warranted for staging if metastasis is suspected.Long-Term ManagementRegular follow-up every 3-6 months for the first 2 years, then annually, focusing on skin examinations for recurrence or new lesions.Patient education on sun protection and skin self-examinations.Consideration of adjuvant therapy, such as interferon, in high-risk patients based on staging and risk factors.
Melanocytic Nevus: Typically symmetric with uniform color and well-defined borders, often present from childhood or adolescence.Solar Lentigo: Common in sun-exposed areas, typically flat and uniformly colored, more common in older adults.Dermatofibroma: Firm, raised nodules that are often brown; usually asymptomatic and not pigmented like melanoma.Basal Cell Carcinoma: Pearly nodules with telangiectasia; less pigmented and often found on sun-exposed areas.Squamous Cell Carcinoma: Typically presents as a scaly red patch or ulcerated lesion; often associated with sun exposure.Post-Inflammatory Hyperpigmentation: Often follows trauma or inflammation; typically uniform in color and borders, fading over time.Other Melanoma Types: Superficial spreading melanoma and nodular melanoma may present differently, but can also be considered in differential diagnosis.
High-Yield PearlsAcral lentiginous melanoma: Most common melanoma subtype in individuals with skin of color, often found on non-sun-exposed areas.Clinical vigilance: Asymmetrical lesions with irregular borders and variegated pigmentation warrant biopsy regardless of the patient's skin type.Biopsy technique: A punch biopsy may be useful, but wide excision is the definitive treatment for diagnosis and management.Staging importance: Sentinel lymph node biopsy is critical in determining the prognosis and further management of melanoma.Education: Patients should be educated on the importance of skin self-examinations and sun protection, regardless of skin type.Remember: Melanoma can occur in unexpected locations and skin types; early detection is key to improving outcomes.
Tags: acral lentiginous melanoma, ALM