Table 3. Details of the seven cases of definitive malignant transformation of PK into skin cancer.

DSAP, disseminated superficial actinic porokeratosis; dx, diagnosis; LE, lower extremity; MT, malignant transformation; PK, porokeratosis; PM, porokeratosis of Mibelli; SCC, squamous cell carcinoma; SCCIS, squamous cell carcinoma in situ; UE, upper extremity; yrs, years

* Patient has had porokeratoses for years, but it is not clear in the notes when exactly it started

** The note clearly stated that a prior DSAP lesion had changed and biopsy was obtained, which showed malignancy

Porokeratosis			Malignant Transformation
Age of dx (yrs)	Type	Type of treatment	Age of dx (yrs)	Duration of PK at time of MT (yrs)	Location	Type of skin cancer	Evidence of MT	Number of other skin cancers	Immune suppression	Radiation therapy
73	DSAP	None	77	4	LE	SCCIS	Histologic confirmation	10	no	no
11	Linear	Cryotherapy, tazarotene	62	51	LE	SCC	Histologic confirmation	1	no	no
71	PM	None	75	4	LE	SCC	By photograph and clinical description**	1	no	no
50	Linear	None	62	12	UE	SCC	By clinical description**	4	yes	yes
41	DSAP	Tretinoin 0.05%	41	0*	LE	SCCIS	Histologic confirmation	3	no	no
72	PM	Silvadene cream and clobetasol	85	13	LE	SCC	By clinical description**	2	yes	no
55	DSAP	5-fluorouracil	51	0*	UE	SCCIS	By clinical description**	14	yes	yes