Granulomas 

It is very common to see granulomas when looking at slides but these can have varied and different aetiologies.

What is a granuloma?

 A granuloma is a localized collection of histiocytes.

How are granulomas classified?

 There are various ways to classify granulomas (of the skin)

1.       Isolated to the skin or associated with systemic diseases

2.       Infectious or non-infectious

3.       Morphologic/histologic features

• a. Sarcoidal/epithelioid, e.g. sarcoid
• b. Tuberculoid/caseating, e.g. TB
• c. Foreign body, e.g. suture material
• d. Suppurative, e.g. fungal infective
• e. Paisading/necrobiotic, e.g. rheumatoid
• f. Elastolytic, e.g. actinic

 

An interesting case:

A youngish Asian gentleman presented to me the other day with uveitis and some skin nodules developing over the upper body.  The nodules were quite non-specific clinically and dermatoscopically but the histology showed sarcoidal type granulomas leading to a diagnosis of sarcoid.

Dermatoscopically, this has some vessels resembling a BCC. Histologically,  there are diffuse sarcoidal type granulomas expanding the dermis. 

 

 

 

 

 

 

 

 

 

 

 

 

 

Take home message

Often granulomas of the skin do not have distinctive diagnostic features. It is important that you correlate clinically (eg age, travel history, ?isolated lesion, PMH)  if you get a report of a granulomatous pattern in the skin.

Regards

Ian Katz