Case Number : Case 3016 - 27 January 2022 Posted By: Saleem Taibjee

Looks granulomatous, reminds me of Granuloma annulare

There are multiple possibilities. There is upper derma edema which could be a lymphedema if the lesion is on the same side as the breast cancer and axillary lymph nodes were removed during radical mastectomy. An infundibular cyst is seen on the right side of the picture, the rupture of which may have given rise to the foreign body granulomatous reaction. Thirdly, as Carina has suggested, the possibility of deep form of GA or even annular elastolytic giant cell granuloma exists if the lesion is on the sun exposed area of the arm.

I'm finding it hard to put all the features into one, unifiying diagnosis.  I suspect the previous breast cancer history might be a red herring.

There are some features making me wonder about lupus: hyperkeratosis, follicular plugging, upper dermal infiltrate with oedema (? mucin) and a hint of basement membrane thickening (final image).  However, I cannot square the granulomatous infiltrate and necrobiosis under a lupus diagnosis.   I did wonder about radiodermatitis, but it is unlikely that the upper arm would have been included in the radiation field and the granulomatous response wouldn't be expected.  Perhaps there's multiple pathology?

A tricky case of interwoven post-irradiation reactions and previous pathological conditions, Rheumatoid Arthritis for example.  I se a radio dermatitis + a palisaded granuloma with fibrinoid necrosis. Why not a triggering effect of radiotherapy in a RA-related background?

Could be a perforating GA. Rhenumatoid nodule also in differential.

could it be drug induced granuloma annulare

[Generalized granuloma annulare and drug-induced immunodeficiency].

Perforating Granuloma annulare secondary to Immune-checkpoint inhibitors is my hypothesis. The previous history of breast cancer may be related to PD-L1 blocker, particularly Atezolizumab.

Interesting discussion and comments about this case.

There was limited clinical information provided. The clinician indicates that the patient was diagnosed with breast cancer 2 years ago, and had surgery, chemotherapy and hormonal treatment, but does not specify the exact treatment. But no history of radiotherapy. The clinical suggestion was granuloma annulare versus nodular prurigo.

Hence I favoured GA. This seems to be an example with unusually dramatic necrobiosis as well as the perforating element. 

Up until recently I hadn't really considered GA as a drug-induced condition. However, I am involved in updating the Granulomatous disorders chapter for the next edition of Rook's Textbook of Dermatology. In so doing, I have come across GA associated with amlodipine (Lim AC, Hart K, Murrell D. A granuloma annulare‐like eruption associated with the use of amlodipine. Australas J Dermatol 2002;43:24–7), as well as associated with anti-TNF treatment in patients with Rheumatoid arthritis (Exarchou SA, Voulgari PV, Markatseli TE, Zioga A, Drosos AA. Immune‐mediated skin lesions in patients treated with anti‐tumour necrosis factor alpha inhibitors. Scand J Rheumatol 2009;38(5):328–31). Krishnakumar's reference is also interesting, suggesting that GA may be triggered by immunosuppressant medications in general. But Igor has now also brought my attention to the recent reports of association with anti-PD1 treatment! I will need to include this in the updated Rook chapter!!

BW, Saleem

Thanks Saleem. Amazing case, as usual!

Great case-thanks for the discussion