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Ultra‐late recurrence of malignant melanoma after 40 years of quiescent disease

Delayed recurrence of melanoma of greater than 10 years since initial diagnosis is thought to be approximately 6% [1]. For this reason current some units advocate up to 10 year follow-up for even thin melanomas [2]. There is evidence melanoma deposits undergo periods of dormancy as exemplified by ultra-late recurrences with upto 20 years disease free intervals reported [3]. However, the exact mechanism that induces dormancy or triggers recurrence is poorly understood. A 73-year-old female had wide excision of a confirmed primary cutaneous melanoma from the left leg aged 19 (1956) we do not have histological sub-data for this tumour. Secondary solitary satellite and in-transit disease was excised aged 20, 25 and 31 (1957, 1962 and 1968) and subsequent left inguinal node dissection for palpable disease was performed aged 33 (1970). There were no surgical complications. At presentation 40 years following her last excision of regional metastatic nodes the patient re-presented to our melanoma service following a period of malaise, fever, rigors, and dysuria. This illness lasted for approximately 9 weeks and a diagnosis of pyelonephritis had been made by physicians. Toward the end of her illness the patient noticed new lesions on her left leg. Excisional biopsy of five discreet pigmented lesions on the left calf and thigh was performed. The histological appearances were those of epidermotropic metastatic melanomas. Histology has shown all of these lesions to be identical. In the following 12 months she had 22 further lesions excised, all from her left leg. These exhibited similar histological patterns of metastatic growth. There was no regional nodal relapse. Furthermore the patient did not receive any adjuvant therapies. Staging computed tomography (CT) showed no evidence of metastastic nodal relapse or visceral disease. This case typifies the unpredictable course of some cutaneous melanomas. There is clear case report evidence that late presentation of metastatic melanoma exists, and in some retrospective series, recurrence over 10 years later can be seen in upto 6% of primary cutaneous melanomas [2,3]. This patient did fall into the minority of those who experience a metastasis over 10 years following primary excision. Data from one large series of patients followed up with primary cutaneous melanoma was reviewed with other reports and estimated a 5-year survival of 55% in those patients who had recurrent regional disease more than 10 years after primary surgery [4]. Of particular interest is the disease free interval of 40 years between groin dissection and new in-transit lesions. There are no previous reports of such latency, however, it is postulated from retrospective analysis of this group of patients that delayed local or regional recurrence can signify less aggressive disease [4], yet a significant proportion succumb to widespread disease within 5 years. It has been observed patients with ultra-delayed presentation of distant skin or visceral metastases have an inferior prognosis to those with local or regional disease [5]. The natural course of disease following local or regional recurrence unfortunately has not been discussed in previous case reports hence it is unknown if further long periods of disease free survival is seen as in this case (Box 1). The time between excision of primary disease and most recent in-transit disease is approximately 54 years.