A 70+ year old male presents with a growing lesion located on the right upper arm. The lesion has been present for over 1 year, and progressed from a small, brown papule, with much more alarming growth in the past 6 months.  He states the lesion is itchy, but not painful; he keeps it wrapped up with an ACE bandage because his wife does not want to see it.  She has been encouraging him to see his family physician but he deferred due to fears of COVID. He has no personal past medical history of skin cancer or other malignancy.

Exam: Significant for approximately 12cm x 7 cm friable nodule on his right upper arm

Question: Following tumor removal, what stains would you expect to be positive?

Click to view enlarged photo.


Tumor cells are highlighted with SOX-10 stain.


Other stains are negative with P63, CK-HMW, Desmin and CD34. Consistent with melanoma.


Cases of giant primary melanoma, defined as lesions at least 10 cm in diameter or 48 mm in thickness, are usually associated with extensive metastatic disease. There are, however, cases of giant primary melanoma without extensive metastasis described in the literature. These cases of giant melanomas without metastases raise the possibility that there could be a distinct subtype of giant melanoma that is locally aggressive, but lacks the tendency to metastasize. Hopefully, this is the case for this patient. 


The patient has been referred to a university melanoma/oncology clinic for workup and treatment.


1. Chong TA et al.  Giant primary melanoma with no apparent metastases: A report of 2 cases.  JAMA Dermatol. 2014;150(5):574-575

2. Ching  JA, Gould  L.  Giant scalp melanoma: a case report and review of the literature.  Eplasty. 2012;12:e51. 

3. Kruijff  S, Vink  R, Klaase  J.  Salvage surgery for a giant melanoma on the back.  Rare Tumors. 2011;3(3):e28. 

4. Harting  M, Tarrant  W, Kovitz  CA, Rosen  T, Harting  MT, Souchon  E.  Massive nodular melanoma: a case report.  Dermatol Online J. 2007;13(2):7. 

6. Panajotovic  L, Dordevic  B, Pavlovic  MD.  A giant primary cutaneous melanoma of the scalp–can it be that big?  J Eur Acad Dermatol Venereol. 2007;21(10):1417-1418. 

By: Mr. Albert Bridger, PA-C; Dr. K. Mireille Chae, MD; Dr. Betsy Wernli, MD; and Dr. Kelli Hutchens, MD