STK11 and neoplasm: Although more cases have been reported, it is still uncertain whether solitary Peutz–Jeghers-type polyp is an incomplete form of PJS or an entity different from PJS.[11,12] No mucocutaneous pigmentation or a family history of PJS in older patients and low risk of tumor development without a malignant change in other organs may be the reasons why a solitary Peutz–Jeghers-type polyp is considered to be a clinical entity different from PJS.[13,14] Hemminki et al[15] identified the gene of PJS (STK11/LKB1) in 1997.