Reticular erythematous mucinosis pathology

Author: Assoc Prof Patrick Emanuel, Dermatopathologist, Auckland, New Zealand, 2014.

Reticular Erythematous Mucinosis or REM is a rare dermatosis characterised by papules and plaques on the upper trunk which often coalesce into a reticulated pattern. Some authors consider this entity a form of cutaneous lupus erythematosus.

Histology of reticular erythematous mucinosis

In REM, sections show a superficial and deep perivascular and periadnexal mononuclear infiltrate (figure 1). The epidermis is uninvolved. The presence of copious mucin between collagen fibres of the dermis is characteristic of the disorder (figures 2, 3).

Special studies for reticular erythematous mucinosis

The mucin may be difficult to appreciate on routine H-E sections. Special stains for mucin (such as colloidal iron or hyaluronic acid) can be helpful to confirm the presence of dermal mucin.

Differential diagnosis of reticular erythematous mucinosis

Scleroedema – This entity also shows mucin deposition but typically lacks an associated inflammatory infiltrate.

Lupus – Tumid lupus can look identical to REM. The clinical presentation can help distinguish these entities. Some authorities consider REM a form of lupus.

Related information

Email Newsletter

Would you like to receive our dermatology updates by email?

SIGN UP

Submit your images

We're seeking high-quality photos of skin diseases.  

SUBMIT A PHOTO

Machine diagnosis

Watch DermNet's proposal to create a 'Skin Disease Image Recognition Tool' - winner of the 2017 'Clinicians' Challenge Active Award' by the NZ Ministry of Health and HiNZ.

Subscribe to our mailing list

* indicates required
DermNet NZ Newsletter