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Tumoral melanosis
Other Resources UpToDate PubMed

Tumoral melanosis

Contributors: Valérie Langevin, Susan Burgin MD
Other Resources UpToDate PubMed


Tumoral melanosis, also known as nodular melanosis or melanophagocytosis, refers to the histopathologic presence of pigment-laden macrophages that has developed at the site of a regressed pigmented lesion. It is a very rare phenomenon, presenting clinically as one or more gray, gray-blue, blackish, or violaceous macules, papules, nodules, or plaques.

Tumoral melanosis is usually observed from completely regressed melanocytic proliferations, including a primary malignant melanoma. In these cases, it may appear at the site of the primary tumor or at sites of cutaneous metastases, and the phenomenon is often associated with the presence of metastatic melanoma. Most recently, melanoma-associated tumoral melanosis has been described in patients with metastatic melanoma undergoing immunotherapy, such as with talimogene laherparepvec, ipilimumab, nivolumab, and pembrolizumab, as well as dabrafenib and trametinib. In these patients, tumoral melanosis usually occurs nearby the primary melanoma excision site or at the site of prior in-transit metastases.

Tumoral melanosis has also rarely been observed after regression of pigmented epithelial lesions, such as pigmented basal cell carcinoma, pigmented Bowen disease, seborrheic keratosis, solar lentigines, pigmented epithelial lined cysts, and benign nevi. Other pathologies described in the literature associated with this finding include mycosis fungoides and blastic plasmacytoid dendritic cell neoplasm (BPDCN).
Even more rarely, tumoral melanosis has been reported in the lymph nodes, known as nodal melanosis. Anecdotally, it has also been found in the visceral organs of 2 patients.


L81.4 – Other melanin hyperpigmentation

402612007 – Hypermelanosis due to neoplasia

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Diagnostic Pearls

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Differential Diagnosis & Pitfalls

The potential clinical and histologic differential diagnoses of causes of tumoral melanosis include other heavily pigmented melanocytic lesions, such as:
It also includes regressed nonmelanocytic tumors such as:
Clinical differential diagnosis of tumoral melanosis:
  • Epithelioid cell or cellular blue nevus and atypical variants (compound blue nevus)
  • Blue nevus–like melanoma
  • Pigmented epithelioid melanocytoma
  • Pigmented spindle cell nevus (Reed nevus)
  • Melanoma

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Management Pearls

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Drug Reaction Data

Below is a list of drugs with literature evidence indicating an adverse association with this diagnosis. The list is continually updated through ongoing research and new medication approvals. Click on Citations to sort by number of citations or click on Medication to sort the medications alphabetically.

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Last Reviewed:03/08/2023
Last Updated:03/09/2023
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Tumoral melanosis
A medical illustration showing key findings of Tumoral melanosis
Copyright © 2023 VisualDx®. All rights reserved.