Article Text

Download PDFPDF
Pitfalls in the diagnosis of lentigo maligna and lentigo maligna melanoma, facts and an opinion
  1. Niloofar Sina,
  2. Zaid Saeed-Kamil,
  3. Danny Ghazarian
  1. Department of Laboratory Medicine and Pathobiology, University Health Network, Toronto, Ontario, Canada
  1. Correspondence to Dr Niloofar Sina, Department of Laboratory Medicine and Pathobiology, University Health Network, Toronto, ON M5G 2C4, Canada;{at}


Lentigo maligna/lentigo maligna melanoma (LM/LMM) affects chronically sun-damaged skin of the head and neck with a slow radial growth phase. It is characterised by predominantly lentiginous proliferation of small, but atypical melanocytes with occasional upward scatter in an atrophic epidermis. It is not uncommon for pathologists to receive partial or scouting biopsies to assess for LM. This makes the interpretation of symmetry and circumscription of the lesions challenging. Therefore, both cytologic and architectural criteria should be taken into consideration to render an accurate diagnosis of melanoma. Moreover, pathologists should be vigilant to avoid missing invasion, as this can change the treatment plan and prognosis. Herein, we aim to discuss important pitfalls in the diagnosis of LMM and its invasive component. Some of these caveats are differentiating between true invasion versus adnexal involvement by the in situ component or an incidental intradermal nevus, detection of microinvasion and multifocal invasion, and recognition of desmoplastic/spindle cell melanoma component.

  • diagnosis
  • melanoma
  • skin

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.


  • Handling editor Runjan Chetty.

  • Contributors NS, as a clinical fellow in dermatopathology at Toronto General Hospital, wrote the first draft of this Viewpoint based on her supervisor’s (DG and ZS-K) guidance and experiences. Then, this paper was reviewed and edited by DG and ZS-K.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Provenance and peer review Not commissioned; internally peer-reviewed.