2000 Jun;25(4):305-7. Alkaptonuric ochronosis presenting as palmoplantar pigmentation.

We describe a 37-year-old woman who presented with palmoplantar pigmentation, thickening and pitting of 4 years duration. Bluish pigmented patches were seen over the sclera of her eyes. Her lumbar spine showed typical calcification of the intervertebral discs. Addition of Benedict's reagent to a urine sample of the patient gave rise to greenish brown precipitate and brownish black supernatant. Alkalinization of urine turned it black. A biopsy of the palmar lesion demonstrated irregular breaking up, swelling and homogenization of collagen bundles in the reticular dermis. Yellow-brown (ochre coloured) pigment was seen lying within the collagen bundles and also freely in the deeper dermis confirming our clinical diagnosis of alkaptonuric ochronosis. To the best of our knowledge this is probably the second report of alkaptonuria presenting with palmoplantar pigmentation.

2016 Jul;95(29):e4332. doi: 10.1097/MD.0000000000004332. Initial misdiagnosis of melanoma located on the foot is associated with poorer prognosis.

Acral melanoma has been reported to be associated with poorer outcomes than melanoma occurring on other cutaneous sites. It has been suggested that part of this disparity in outcomes may be related to delay in diagnosis. Therefore, we have analyzed the rate of misdiagnoses in patients with melanoma located on the foot and have characterized the influence on the clinical course and survival of the patients. A prospective, computerized melanoma database at the Skin Cancer Center of the University Hospital Essen, Germany was used to identify patients with histologically confirmed melanoma located on the foot between 2002 and July 2013 for subsequent analysis. A cohort of 151 patients diagnosed with primary melanoma located on the foot was identified. One hundred seven patients qualified for subsequent analysis. Forty-two patients were male (39.3%) and 65 (60.7%) were female; the mean age at first diagnosis was 61.6 years (median 66 years). The youngest patient was 19 years, the oldest 88 years old.Of the 107 patients analyzed, 32 (30%) were initially misdiagnosed. Misdiagnoses included chronic wounds, nevi, hematoma, fungal infections, warts, and paronychia. Misdiagnosis caused a median delay in diagnosis of 9 months. The 5-year disease-free survival rate (47.8% vs 72.7%) and the 5-year overall survival rate (63.5% vs 88.4%) were statistically significant lower in the misdiagnosis cohort.The awareness of potentially overlooked melanoma located on the foot has to increase among physicians.To improve early detection and, thus, the prognosis of patients with melanoma located on the foot, taking a biopsy from any suspicious lesion should be taken into consideration as soon as possible.

2008.09.014. Melanoma of the feet: misdiagnosed and misunderstood.

Acral lentiginous melanoma of the foot is a relatively rare but often very aggressive variant of melanoma. More commonly identified in patients with darker skin, diagnosis of the lesions is often delayed because the area is not routinely examined by patients or primary care physicians. In addition, these lesions often mimic other entities, including vascular lesions and infections. Greater awareness of this entity and performing appropriate biopsies will result in more timely diagnoses and improved survival.

1946 Aug;54:226. Melanoma of the heel.

1955;29(3):238-40. Malignant melanoma; the difficulty of early diagnosis.

2011 Jul 26. Prognostic variables and surgical management of foot melanoma: review of a 25-year institutional experience.

INTRODUCTION: Cutaneous foot melanoma is rare, challenging to manage, and not adequately examined in the literature. This study evaluated the prognostic variables and surgical management of foot melanoma. MATERIALS AND METHODS: Foot melanoma cases managed at an academic center from 1985 to 2010 were retrospectively reviewed. RESULTS: 46 patients were identified with a broad range of demographic characteristics. Overall recurrence was 32.6%: 19% acral lentiginous, 57% nodular, 66% superficial spreading, 30% melanoma unspecified, 50% severely atypical; 53% ulcerated, 23% nonulcerated; 29% on the dorsum of the foot, 17% heel, 60% ankle, 22% toe, 50% plantar; 0% <1 mm thick, 47% 1-4 mm, 33% >4 mm. 13 had positive nodes, 4 (31%) of whom recurred. Prognostic factors and recurrence did not correlate, and survival was 96% with a median followup of 91 months. CONCLUSIONS: Aggressive management of foot melanoma may result in excellent long-term survival even following disease recurrence.

2017 Jul;96(29):e7541. doi: 10.1097/MD.0000000000007541. Malignant melanoma misdiagnosed as diabetic foot ulcer: A case report.

RATIONALE: Acral lentiginous melanoma (AML) does not exhibit the classic signs of malignant melanoma. ALM is frequently misdiagnosed because of its unusual sites and atypical clinical morphologies, which lead to poor prognosis. PATIENT CONCERNS: A female patient aged 78 years was presented to our center with two ulcers on her right foot. Diabetic foot ulcer was considered as the primary diagnosis. The ulcers failed to improve after 2 weeks' therapy. DIAGNOSES: An incisional biopsy of the lesion revealed malignant melanoma. INTERVENTIONS: The patient received wide excision, skin grafting as well as biotherapy. OUTCOMES: The lesion was healed and no other metastasis has been founded until now. LESSONS: Clinicians must maintain a high level of suspicion in distinguishing malignant melanoma from other more benign skin lesions of the foot. The need for early biopsy of ulcer, even when clinical suspicion is low, can not be overemphasized. Only in this way can we reduce misdiagnosis rate and improve survival rate in patients with foot ulcer.