suspected of having ccs but showing the presence of a normal clyd gene based on the genetic testing of blood leukocytes, genetic testing of tumor tissue can confirm the diagnosis of ccs. these methods differentiate ccs not only from sporadic cylindromas, spiradenomas, trichoepitheliomas, and their malignant counterparts but also from various skin tumor disorders with which they may be confused such as the birt–hogg–dubé syndrome, tuberous sclerosis, neurofibromatosis, cowden syndrome, marie-unna hypotrichosis, and multiple scalp trichilemmal cysts. treatment and prognoses ccs is an inherited, life-long, familial disease which currently is incurable. all members of ccs families should be tested for the cyld gene in order to identify those that do as well as those that do not carry an inactivating mutation in this gene. testing for this gene is particularly important in cases with minimal evidence of the disease (e.g. milia, see presentation section) and may need to test tumor rather than blood leukocyte samples in individuals with mosaic, deep intronic, or copy number variation mutations (see genetic section). all individuals who are found to carry the inactivated familial cyld gene mutation should receive genetic counselling which may include: information on limitations in the ability to predict the severity of ccs between individuals, families, and generations; family planning; prenatal testing; preimplantation genetic diagnosis; and the need for follow-up evaluations. individuals with ccs should get full-skin and possibly other organ (e.g. salivary gland) examinations performed yearly in routine cases, every 2–3 months in cases where their tumors show rapid growth or the formation of numerous new skin tumors, and immediately in cases where their tumors develop signs of malignancy (e.g. tumor ulceration, very rapid growth, pain, intermittent bleeding, color changes, or tethering to an underlying bone or in cases that develop sudden onset of organ dysfunction such as breathlessness which may reflect lung metastases). benign ccs tumors the treatments for benign ccs tumors are directed at removing tumors that cause unacceptable symptoms (e.g. pain, ulceration, bleeding, disfigurement, sexual dysfunction, or occlusion of a passageway such as an ear canal). methods for these removals include surgical excision, electrodessication with curettage, dermabrasion, cryotherapy, or carbon dioxide, argon, or er:yag laser surgery. where indicated by cosmetic or functional considerations, these treatments are followed by plastic and/or reconstructive surgeries such as flap surgery (i.e. normal tissue with its blood supply intact is lifted from a donor site and moved to the surgical site). these treatments are often used repeatedly in individuals with numerous tumors, recurrent tumors, or newly formed tumors; the treatments may also be extensive with, for example, up to 1 in 4 individuals with ccs requiring complete surgical removal of their scalps. malignant ccs tumors primary ccs tumors that are known or suspected to be malignant and accessible metastatic tumors are currently treated with wide local excisions often followed by adjuvant radiotherapy. wide local excision is used in order to remove all malignant cells while adjuvant radiotherapy is used to kill any malignant cells that remain behind after surgery. malignant ccs tumors uncommonly metastasize to distant, non-cutaneous sites. histopathologically defined low-grade tumors metastasize less often than their high-grade counterparts. since past studies on the treatment of malignant ccs tumors often included, but did not clearly distinguish between, sporadic and familial cylindrocarcinoma, spiradenocarcinoma, and trichoblastic carcinoma tumors and since malignant ccs tumors are extremely rare, there are no clear data on the percentage of malignant ccs tumors that recur, metastasize, and become lethal. clearly, however, ccs malignant tumors can produce each of these undesirable results. the best treatment regimens for ccs malignant tumors are unclear and require further study. drug treatments for ccs tumors trial studies have tested the therapeutic effects of drugs that inhibit the nf-κb pathway on ccs tumors. these drugs include topical (i.e. applied directly to the tumors) aspirin or other salicylic acid-like drugs,. in another drug trial study, an inhibitor of trk receptors, topical pegcantratinib, was similarly tested. none of these treatments proved to have appreciable anti-tumor actions beyond occasional short-term effects. one individual with ccs tumors was treat with vismodegib, an inhibitor of the smoothened receptor and thereby the hedgehog signaling pathway and a second individual was treated with oral aspirin plus adalimumab (a monoclonal antibody that neutralizes tumor necrosis factor alpha). both of these individuals showed slowly developing, modest improvements in there skin tumors although the individual treated with aspirin plus adalimumab showed no improvements in his multiple metastatic tumors. further studies are needed to determine if these or any other drugs are effective in treating ccs tumors.