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Diagnosing And Treating A Rare Case Of Ungual Melanoma
Mindful of diagnostic challenges, this author presents the treatment of ungual melanoma in a 76-year-old patient who presented with a longstanding lesion.
A 76-year-old female presented to a podiatrist with a lesion on the right hallux. The patient stated the lesion was getting progressively worse over the past four days. She had the black/dark discolored lesion on her right hallux for years but she noticed the lesion increase in size. The podiatrist referred her to the emergency room.
The patient’s past medical history includes diabetes, hypertension and breast cancer. Her past surgical history includes a right breast mastectomy, appendectomy and cataract surgery. She had no history of smoking or alcohol usage. The patient denied any recent nausea, fever or chills. The patient received IV ampicillin/sulbactam 3 g in the emergency department.
The physical examination showed the patient’s neurovascular status was intact. Capillary fill time was less than three seconds to all ten digits. The right hallux showed a soft tissue mass dorsally (see photos) that was bleeding. A fungating, hyperpigmented nodular lesion was present at the right hallux. There was pain upon palpation of the great toe. No purulence or malodor were present.
Blood cultures were negative. The patient’s lactic acid level was 0.6 mmol/L. The white blood cell count was 5.20, the C-reactive protein level was 0.03 mg/L and the erythrocyte sedimentation rate (ESR) was 255. Her HbA1c was 7.3. Pulse volume recordings showed normal arterial hemodynamics in the lower extremities bilaterally. X-rays showed a hallux soft tissue mass without evidence of underlying osseous abnormality.
Magnetic resonance imaging (MRI) of the first toe dorsal nail bed showed a 2.6 x 1.9 x 1.5 cm lobulated mass with internal small calcifications bordering the dorsal first distal phalangeal cortex without invasion of the underlying bone. There was no evidence of osteomyelitis.
The patient went to the operating room three days after hospital admission. With the patient under intravenous sedation along with a local anesthetic and a tourniquet, surgeons performed a right hallux amputation with the base of the proximal phalanx remaining. Surgeons placed sterile ½-inch packing into the surgical site before closure.
Surgeons removed the packing the next day. The pathology report stated the lesion was an in situ invasive malignant melanoma, was ulcerated and 12 mm at its greatest thickness. The resection margin, which included skin, soft tissue and bone, was free of tumors. Melanoma invaded the subcutaneous layer but did not invade the bone.
A Closer Look At The Pathology Of The Lesion
The 7 x 3 x 2 cm specimen, fixed in formalin, consisted of an amputation of the right great toe. The dorsal surface skin surgical margin is 2.5 cm away from the bone surgical margin. The plantar skin surgical margin is 2 cm away from the bone surgical margin. The nail was not present in the specimen.
A 3.5 x 3.0 cm black discoloration area is visible on the dorsal surface and is 1 cm away from the closest surgical margin. A dark brown fungating tumor measuring 3 x 2 x 1 cm is visible within the black discoloration area. The fungating tumor is 1.4 cm away from the closest dorsal skin surgical margin and 4 cm away from the bone surgical margin. On cut sections, the tumor appears to be 1 cm thick. There is not gross involvement of the bone. Under the microscope, the tumor’s greatest dimension measures 3.5 cm and the maximum tumor thickness measures 1.2 cm for the maximum thickness.
Melanoma invades the subcutis and is very close to bone, but does not invade into bone. There is no involvement of invasive carcinoma nor in-situ melanoma in the margin. The invasive carcinoma is 14 mm away from the closest peripheral margin and the in-situ melanoma is 10 mm away from the closest peripheral margin. The mitotic rate is >10/mm2. Microsatellitosis is present. Lymphovascular invasion is not visible. Tumor regression is present as it involves less than 75 percent of the lesion. The tumor growth pattern is vertical. The histologic type is melanoma that is not otherwise classified.1
What You Should Know About Ungual Melanoma
Ungual melanoma is a rare disease, which is difficult to diagnose and has a poor prognosis. Ungual melanomas are localized either under or around the nail. They are a subgroup of acral lentiginous melanomas. The cross sections of the specimen of this patient show the melanoma is under and around the nail bed. It is more common in dark-skinned patients than Caucasians. The most frequent localizations of ungual melanoma are the thumb and the big toe followed by the index and middle finger. The etiology of ungual melanoma is not clear. Unlike with other melanomas, the sunlight or ultraviolet light is a highly improbable etiology. The relationship between trauma and ungual melanoma is controversial.2
Generally, acral lentiginous melanomas including nail melanomas have a poor prognosis.2 The melanoma in this patient has some features that indicate a poor prognosis: the ulcer, the vertical growth pattern, the melanoma invading to subcutis, microsatellitosis and the high mitotic rate.
Obtaining a thorough patient history, including medical history, family history, sun exposure and the presence of nevi throughout the body, is very important. It is also vital to ascertain the “ABCDE” of the skin lesion: asymmetry, border irregularity, color variation, diameter >6 mm and elevation of the lesion are all significant for early diagnosis of a melanoma.3
Biopsy is the gold standard to diagnose melanomas. A biopsy helps reveal the level of invasion as well as the thickness of the melanoma. In this specific case study, the melanoma was a Clark’s level V and Breslow’s level V melanoma.1
Clark’s Level (level of invasion)
I: tumor cells above basement membrane
II: into papillary dermis
III: between papillary dermis and reticular dermis
IV: into reticular dermis
V: into subcutaneous tissues
Breslow’s Depth (thickness)
I: less than or equal to 0.75 mm
II: 0.76 mm – 1.5 mm
III: 1.51 mm – 2.25 mm
IV: 2.26 mm – 3.0 mm
V: greater than 3.0 mm
In Conclusion
The patient’s treatment was the standard of care. The patient’s skin lesion in the case study showed the ABCDEs of a melanoma. The lesion was asymmetrical in nature, the borders were irregular, color discoloration was present, the diameter was greater than 6 mm and elevation of the skin lesion was prominent as well.
When there is a high index of suspicion for a melanoma lesion, one should rule out malignancy, involve other specialties, order advanced imaging to detect involvement of the lesion and biopsy. For this case study, we treated the patient with the most appropriate care. As noted, one should always be highly suspicious of potential melanomas due to their aggressive nature, misdiagnosis and mortality rate.
Dr. Khalifa is a third-year resident at Northwell Health-Staten Island in Staten Island, NY.
The author thanks William Lopez, DPM, John Sottile, DPM, Jocelyn Villanueva, MD and Wei Xue, MD at Northwell Health-Staten Island, NY for their help with the case study.
References
1. Balch CM, Soong SJ, Gershenwald JE, et al. Prognostic factors analysis of 17,600 melanoma patients: validation of the American Joint Committee on Cancer melanoma system. J Clin Oncol. 2001; 19(16):3622-34.
2. Gosselink CP, Sindone JL, Meadows BJ, et al. Amelanotic subungual melanoma: a case report. J Foot Ankle Surg. 2009; 48(2):220-224.
3. Frey J, Shimek C, Woodmansee C, et al. Aggressive digital papillary adenocarcinoma: A report of two diseases and review of the literature. J Am Acad Dermatol. 2009; 60(2):331-339.
4. Albreski D, Sloan SB. Melanoma of the feet: Misdiagnosed and misunderstood. Clin Dermatol. 2009; 27(6):556-563.
5. Haneke E. Ungual melanoma – controversies in diagnosis and treatment. Dermatol Ther. 2012; 25(6):510-24
6. Jaafar H. Intra-operative frozen section consultation: concepts, applications and limitations. Malays J Med Sci. 2006; 13(1):4-12.
7. Tanis PJ. Frozen section investigation of the sentinel node in malignant melanoma and breast cancer. Ann Surg Oncol. 2001; 8(3):222-226.
8. Ramanujam C, Kearney T, Zgonis T, et al. A case report of malignant melanoma of the great toe. J Foot Ankle Surg. 2009; 48(2):225-29.
