Metastases to the nail unit and distal phalanx: a systematic review

Cutaneous metastasis of a sarcomatoid–rhabdoid renal tumor to a distal phalanx

“…1,3 In contrast, CM to the nail unit/distal phalanx are highly uncommon, making up a scarce 1% of all acral metastases, and are usually distant to the primary neoplastic site, which is usually the lung, followed by the kidneys. 5,6 Additionally, this type of CM usually affects one single digit of the upper extremities. 5 This differs from chemotherapy-linked paronychia which can also be seen in oncologic patients, especially under treatment with taxanes or epidermal growth factor receptor inhibitors, that usually involves several digits and is thought to be caused by an alteration of matricial keratinocytes in the nail unit.…”

“…5,6 Additionally, this type of CM usually affects one single digit of the upper extremities. 5 This differs from chemotherapy-linked paronychia which can also be seen in oncologic patients, especially under treatment with taxanes or epidermal growth factor receptor inhibitors, that usually involves several digits and is thought to be caused by an alteration of matricial keratinocytes in the nail unit. 7 Histology is mandatory in the diagnosis of CM, showing atypical cell proliferations in the dermis/hypodermis, while the epidermis is usually spared in the initial phases.…”

“…Clinically, CM usually present as rapidly growing subcutaneous lesions frequently located in proximity to the primary tumor 1,3 . In contrast, CM to the nail unit/distal phalanx are highly uncommon, making up a scarce 1% of all acral metastases, and are usually distant to the primary neoplastic site, which is usually the lung, followed by the kidneys 5,6 . Additionally, this type of CM usually affects one single digit of the upper extremities 5 .…”

“…Albeit metastasectomy is still recommended whenever possible, 8 average 6‐month survival rate in CM is still under 50% 3 . Therapies specifically intended for metastatic RCC include nephrectomy, radiotherapy, immunotherapy, and tyrosine kinase inhibitors 5,9 …”