A novel APC mutation associated with Gardner syndrome in a Chinese family.

Gardner syndrome (GS) is a specific form of familial adenomatous polyposis (FAP), which manifests as colorectal polyps, multiple osteomas and soft tissue tumors, and in the oral cavity as osteomas of the jaws, odontomas, and abnormal tooth counts. The underlying cause of GS is attributed to mutations in the APC gene. Mutations in this gene disrupt the normal functioning of the protein and lead to the development of GS. To further investigate GS, a family affected by the syndrome was selected from Dongguan, Guangdong Province. The family members underwent a comprehensive survey, which involved collecting clinical data and peripheral venous blood samples. The samples were then used for genetic analysis. Whole exome sequencing (WES) and Sanger sequencing techniques were utilized to screen and identify specific mutation sites in the APC gene. The clinical findings for the GS family included the presence of gastrointestinal polyps and odontomas. After analyzing the genetic sequencing results, a novel mutation site c.4266dupA on the APC gene was found in the patients, which leading to the APC protein truncation. As a result of this study, it is suggested that odontoma may be an early indicator of GS. Additionally, the identification of this novel mutation site in the APC gene expands the known spectrum of genetic mutations associated with the disease. This discovery has significant implications for the early diagnosis of GS, thus enabling timely intervention to reduce the risk of developing colon cancer and other related diseases.

A role for total alloplastic temporomandibular joint replacement in Gardner syndrome.

Gardner syndrome (GS) is a rare autosomal dominant disorder that can present with craniomaxillofacial abnormalities. The identification of osteomas or craniomaxillofacial abnormalities can therefore serve as a marker of this condition, facilitating early referral and diagnosis. A 17-year-old female with GS was referred for the management of severe limited mouth opening, causing a major problem for routine endoscopy to monitor the gastrointestinal alterations of GS. Clinical and radiological evaluations showed multiple osteomas in the mandibular angle, condylar and coronoid regions bilaterally and maximum mouth opening of 8 mm. The patient underwent surgery for osteoma removal and bilateral customized alloplastic total temporomandibular joint replacement (TMJ-TJR). At the 2-year follow-up, the patient showed improvements in quality of life, with a maximum mouth opening of 34 mm, allowing routine upper endoscopy to be performed. This is the first report of GS, a rare and challenging craniomaxillofacial abnormality, treated with TMJ-TJR. A comprehensive overview of the patient's clinical presentation, diagnostic assessment, treatment planning, and outcomes is provided.

A Rare Case of Multiple Gastrointestinal Stromal Tumors Coexisting with a Rectal Adenocarcinoma in a Patient with Attenuated Familial Adenomatous Polyposis Syndrome and a Mini Review of the Literature.

BACKGROUND: Multiple gastrointestinal stromal tumors (GISTs) are extremely rare entities that exist either as spontaneous GISTs or as part of various syndromes, such as Carney's triad and type I neurofibromatosis (NF1). Attenuated familial adenomatous polyposis (AFAP) is a variant of familial adenomatous polyposis (FAP) with a milder clinical presentation. Both GISTs and AFAP have been reported to coexist with colorectal cancer, but the coexistence of GISTs and AFAP has never been reported in the literature before. CASE REPORT: A 45-year-old male patient with known AFAP arrived scheduled for a total colectomy and ileo-rectal anastomosis due to the malignancy of one of the previously biopsied polyps of the upper rectum. Intraoperatively, multiple nodular tumors were found at the jejunum within a length of 45 cm, for which an enterectomy and enteroanastomosis were performed. A histopathological examination of the whole colectomy specimen confirmed the presence of multiple polyps in the large intestine along with a rectal invasive adenocarcinoma. At the same time, in the examined part of the small intestine, 15 GISTs sized from 0.5 to 2.0 cm of prognostic group I, were identified. The patient's postoperative course was uncomplicated. CONCLUSION: Multiple GISTs may present as an asymptomatic disease, and the same thing is true for colorectal cancer. Therefore, the appropriate screening is crucial for entities such as AFAP, since the surgery was performed because of the malignant transformation in one of the polyps and revealed multiple GISTs, as well.

Rare case of multiple and perforating pilomatrixomas in a young girl with lymphovascular malformation reveals a potential new disease association.

This report details the case of a girl of primary school age who was referred to our plastic surgery department with an ulcerating lesion on the nape of her neck. A firm mass was palpable in the underlying subcutaneous tissue. This lesion was accompanied by two smaller firm nodules: one in the adjacent tissue and another in the left preauricular region. Ultrasound and MRI demonstrated multiple calcified nodules confined to the subcutaneous tissue. An incisional biopsy of the ulcerating lesion confirmed a diagnosis of perforating pilomatrixoma; the lesion was subsequently excised, with no sign of recurrence at 3-month follow-up. The patient had a history of lymphovascular malformation (LVM) and a paternal history of Gardner's syndrome. Pilomatrixoma and Gardner's syndrome have a well-documented association in existing literature; aberrant Wnt/beta-catenin signalling is common to both. Recent laboratory studies suggest this pathway is also implicated in the pathogenesis of LVM.

El llamado síndrome de alienación parental y sus derivaciones / The so-called parental alienation syndrome and its derivations

La denigración de un progenitor por el otro es uno de los efectos más dañinos para el menor en situaciones de ruptura familiar, si bien el llamado síndrome de alienación parental (Gardner) como supuesto trastorno mental infantil, no ha obtenido la aceptación en las clasificaciones psiquiátricas internacionales, ni la necesaria validez y soporte científico, por lo que profesionales de la salud mental, peritos y juristas deberían evitar su empleo. En su lugar, cabe valerse de los criterios diagnósticos contemplados por las clasificaciones psiquiátricas diagnósticas internacionales que describimos. Es esencial establecer el diagnóstico diferencial a partir del síntoma del rechazo hacia un progenitor, cuestión que entraña dificultad y que puede requerir el concurso de un equipo multidisciplinar para valorar adecuadamente todos los aspectos evaluables. Los profesionales han de obrar con conocimiento de los límites de su ciencia, aportando aquellos datos y conclusiones que sean legítimos y válidos según tal premisa. (AU)

The denigration of one parent by the other would be one of the most damaging effects for the child in situations of family breakdown, although the so-called parental alienation syndrome (Gardner) as a supposed childhood mental disorder, has not obtained acceptance in psychiatric classifications nor the necessary validity and scientific support, so its use by mental health professionals, experts and lawyers should be avoided. Instead, one can use the diagnostic criteria contemplated by the international diagnostic psychiatric classifications that we describe. It is essential to establish the differential diagnosis based on the symptom of rejection of a parent, an issue that involves difficulty and may require the assistance of a multidisciplinary team to adequately evaluate all the evaluable aspects. Professionals must act with knowledge of the limits of their science, providing those data and conclusions that are legitimate and valid according to this premise. (AU)

Giant mesenteric fibromatosis associated with non-Hodgkin lymphoma. A case report and literature review.

BACKGROUND: Mesenteric fibromatosis is a benign locally-aggressive mesenchymal neoplasm that lacks the potential for metastasis. It is related to Gardner's Syndrome, previous trauma, abdominal surgery, and prolonged intake of oestrogen. Differentially diagnosing this from similar tumours is crucial in order for establishing the appropriate treatment and only immunohistochemical features can be used for a definitive diagnosis. Although medical therapies play a role in the treatment of mesenteric fibromatosis, surgical resection is the gold-standard procedure. METHODS: Our case study is a 40-year-old male with a concomitant diagnosis of non-Hodgkin lymphoma and mesenteric fibromatosis, not associated with any of the risk factors mentioned above. We performed CT and PET scans and observed a vascularised and well-defined mesenteric centre-abdominal hypermetabolic solid mass in contact with the gastric body, duodenum, body and tail of the pancreas, transverse colon, and spleen. An ultrasound-guided tru-cut biopsy revealed features suggestive of mesenteric fibromatosis. RESULTS: An elective laparotomy was carried out and a giant mass, arising from mesentery, was excised, including a partial gastrectomy and segmental resection of the transverse colon. Distal pancreatectomy, small bowel resection and successive splenectomy were performed due to a large hypertensive component. The postoperative period was uneventful. The histopathology of the surgical pieces was compatible with intra-abdominal desmoid fibromatosis. CONCLUSION: As far as we know from the literature, this is the largest mesenteric fibromatosis tumour ever to be excised. We also noticed that this is the first reported case of the concomitant presence of mesenteric fibromatosis and non-Hodgkin lymphoma that is not related to any of the described risk factors. Further research is needed to establish what type of association this presentation may indicate.

Percutaneous ultrasound-guided radiofrequency ablation for giant desmoid tumors of the intra-abdominal cavity in a patient with Gardner syndrome.

Gardner syndrome (GS) is a rare variant of familial adenomatous polyposis, leading to numerous intra- and extracolonic lesions. Extracolonic lesions of GS are most common with desmoid tumors (DTs) in the abdominal wall, intra-abdominal cavity, and mesentery. Surgery remains the primary treatment for DTs; however, the patients are challenged with the high recurrence rate after surgical resection, and wide resection often results in debilitating loss of function. This study presents a case of a 47-year-old female with GS who had undergone total colectomy and ultra-low anastomosis of the ileal anal canal, and she developed giant DTs in the intra-abdominal cavity. The patient underwent ultrasound-guided percutaneous radiofrequency ablation (RFA) for intra-abdominal DTs in September 2014, October 2015, and January 2016. Palliative RFA significantly slowed the progression of the tumor and improved the symptoms of abdominal compression; thus, it is a possible therapeutic option for intra-abdominal unresectable DTs in patients with GS.

Síndrome de Gardner: informe de un caso y revisión de la literatura / Gardner syndrome: case report and literature review

El síndrome de Gardner es una enfermedad genética de herencia autosómica dominante, presenta múltiples manifestaciones craneofaciales caracterizadas por hipercrecimientos óseos conocidos como osteomas, riesgo de desarrollo de pólipos gastrointestinales con alto potencial de malignidad y de tumores o quistes en piel, así como alteraciones dentales, entre las que destacan la presencia de dientes supernumerarios, retenciones dentarias, permanencia de dientes deciduos y odontomas, estas últimas de gran importancia para el odontólogo. Se trata de una enfermedad que afecta a mujeres y hombres de forma indistinta, no obstante, su prevalencia es mayor en el sexo femenino. El objetivo del presente artículo es explicar las manifestaciones clínicas y radiográficas dentales y craneofaciales del síndrome de Gardner mediante la presentación de un caso clínico y revisión de la literatura (AU)

Gardner syndrome is a genetic disease of autosomal dominant inheritance, it presents multiple craniofacial manifestations characterized by bone overgrowths known as osteomas, risk of development of gastrointestinal polyps with high potencial of malignancy, and skin tumors or cysts, as well as dental alterations, among the characteristics of the presence of supernumerary teeth, dental retention, permanence of deciduous teeth and odontomas, the latter of great importance for the dentist. It is a disease that affects women and men indistinctly, however, its prevalence is higher in the female sex. The aim of this article is to explain the dental and craniofacial clinical and radiographic manifestations of Gardner syndrome by presenting a clinical case and a review of the literature (AU)

Tumor desmoide abdominal gigante en puerperio: caso clínico y revisión de la literatura / Giant abdominal desmoid tumor during the puerperium: Case report and review of literature

Introducción. Los tumores desmoides o fibromatosis agresiva corresponden a neoplasias mesenquimales poco frecuentes. Son tumores localmente agresivos que ocurren especialmente en jóvenes, no desarrollan metástasis a distancia, pero se asocian con invasión locorregional y alta tasa de recurrencia después de la resección. Su etiología es desconocida, pero se ha asociado al síndrome de Gardner, trauma, embarazo, estados hiperestrogénicos y puerperio. El objetivo de este artículo fue hacer una revisión sobre el tema a propósito de un caso clínico. Caso clínico. Se presenta el caso de una paciente puérpera con progresivo y rápido aumento del volumen abdominal. Se realizó una tomografía computarizada de abdomen y pelvis que confirmó la presencia de una masa intraperitoneal bien definida. La paciente fue operada con escisión de la masa y confirmación histológica de tumor desmoide a partir de la muestra de patología. Discusión. Los tumores desmoides tienen una incidencia de 2 a 4 casos por millón de habitantes por año, con leve predominio en el sexo femenino y representan menos del 3 % de los tumores de partes blandas. Aunque el tumor se puede ubicar a nivel intraabdominal o en la pared, la ubicación más común es en las extremidades. Conclusiones. La sospecha y detección del tumor desmoide es fundamental, así como su adecuado estudio, para determinar el tratamiento quirúrgico como fue realizado en este caso

Introduction. Desmoid tumors or aggressive fibromatosis correspond to rare mesenchymal neoplasms. They are locally aggressive tumors that occur especially in young people, they do not develop distant metastases, but are associated with locoregional invasion and a high recurrence rate after resection. Its etiology is unknown, but it has been associated with Gardner syndrome, trauma, pregnancy, hyperestrogenic states, and puerperium. The objective of this article was to review the topic based on a clinical case. Clinical case. The case of a puerperal patient with progressive and rapid increase in abdominal volume is presented. An abdominal and pelvic CT scan was performed, which confirmed the presence of a well-defined intraperitoneal mass. The patient underwent surgery with excision of the mass and histological confirmation of a desmoid tumor from the pathology sample. Discussion. Desmoid tumors have an incidence of 2 to 4 cases per million inhabitants per year, with a slight predominance in females, and represent less than 3% of soft tissue tumors. Although the tumor can be located intra-abdominal or in the wall, the most common location is in the extremities. Conclusions. The suspicion and detection of the desmoid tumor is essential, as well as its adequate study to determine the surgical treatment as it was done in this case

Cutaneous desmoid-type fibromatosis: A rare case with molecular profiling.

Fibromatoses encompass a broad group of histopathologically similar fibroblastic/myofibroblastic proliferations with divergent clinical manifestations and behavior. Deep (desmoid-type) fibromatoses are typically large, rapidly growing, and locally aggressive tumors that occur in the abdominal wall, mesentery, and extra-abdominal soft tissue, principally the musculature of the trunk and extremities. Most sporadic cases of desmoid fibromatosis harbor inactivating mutations in CTNNB1, the gene encoding beta-catenin. Tumors occurring in the context of familial adenomatous polyposis and Gardner syndrome bear inactivating mutations in APC. By contrast, mutations in CTNNB1 or APC have not been identified in cases of superficial fibromatosis. Cutaneous involvement by desmoid fibromatosis is exceedingly rare. Here we present a 78-year-old male with desmoid-type fibromatosis arising in the dermis of the right medial calf with a pathogenic mutation in CTNNB1 and a variant of unknown significance in APC.

Torpedo-like lesions in the ocular fundi of Gardner syndrome: hiding in plain view.

Background: The coexistence of fundus torpedoes and Gardner syndrome was initially reported in 1989 and 1992 by Gass and Roseman. Gardner syndrome is a dominantly inherited disease characterized by a multitude of potentially lethal gastrointestinal polyps. Over the ensuing quarter century, several publications demonstrated uncommon, but easily recognized, fundus lesions called Torpedo Maculopathy in apparently normal individuals. These fundus abnormalities were thought to be single and isolated without systemic associations. During the same period of time, a variety of nonspecific fundus abnormalities were described in Gardner syndrome, which, in retrospect, included highly specific lesions that closely resembled macular torpedoes and sometimes were indistinguishable from them.Patient and methods: We now report a confirmed case of Gardner syndrome with numerous fundus torpedoes, and carefully analyze the voluminous literature of both Gardner syndrome and Torpedo Maculopathy.Results: We demonstrate shared features of the fundus lesions in both diseases, and hypothesize that they may have genetic as well as ophthalmoscopic similarities in common.Conclusions: We therefore recommend that individuals with classic isolated torpedoes undergo evaluations for mutations in the Gardner gene (Adenomatous polyposis coli) and for the presence of gastrointestinal polyps and other systemic features of Gardner syndrome. We also suggest that apparently normal individuals, who are genetically related to patients with known classic torpedoes, undergo inspection of their fundi for the possible presence of characteristic lesions.

Gardner-associated fibroma of the neck: role of a multidisciplinary evaluation for familial adenomatous polyposis diagnosis.

INTRODUCTION: Familial adenomatous polyposis (FAP) is a hereditary autosomal dominant disorder characterized by the development of multiple adenomas in the colon and rectum with a lifetime risk of 80%-100% to develop colorectal cancer if undetected or untreated. Gardner-associated fibroma (GAF) is a rare, benign soft tissue lesion with uncertain pathogenesis. GAF is generally associated with FAP in its clinical variant, called Gardner syndrome (GS). CASE DESCRIPTION: A 16-year-old boy with no comorbidities and no significant medical history was referred to the Unit of Hereditary Digestive Tract Tumours, Department of Surgery, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy, for genetic counselling after surgical removal of a right anterior cervical paramedian fibroma. The histopathology on the specimen led to the diagnosis of GAF. He had no family history for colorectal cancer or gastrointestinal polyposis and denied any gastrointestinal symptoms. Physical examination showed a small frontal osteoma and colonoscopy showed the presence of multiple small sessile polyps (>100 polyps, diameter <5 mm) diffusely present on the large bowel. Genetic testing revealed a pathogenic germline variant in the APC gene. The predictive genetic test on the patient's parents and sister was negative for the identified APC mutation; therefore, the patient carried an apparent de novo germline mutation. CONCLUSIONS: GAF may represent a sentinel sign of FAP, preceding gastrointestinal symptoms and endoscopic findings. A careful multidisciplinary approach is determinant for correct and early diagnosis of FAP.

Accumulated genetic mutations leading to accelerated initiation and progression of colorectal cancer in a patient with Gardner syndrome: A case report.

RATIONALE: Gardner syndrome is a rare autosomal dominant disorder with a high degree of penetrance, which is characterized by intestinal polyposis, osteomas, and dental abnormalities. Majority of patients with Gardner syndrome will develop colorectal cancer by the age of 40 to 50 years. Mutations in the adenomatous polyposis coli gene are supposed to be responsible for the initiation of Gardner syndrome. PATIENT CONCERNS: A 22-year-old Chinese female was admitted to our hospital due to abdominal pain and bloody stool. DIAGNOSIS: The patient presented with multiple intestinal polyposis, desmoid tumors, and dental abnormalities was diagnosed as Gardner syndrome and further examination revealed a colon tumor. INTERVENTIONS AND OUTCOMES: Patients were implanted with stents to alleviate bowel obstruction, and were treated with oxaliplatin combined with 5-Fu for 4 cycles, but the efficacy was not good. We performed next generation sequencing of 390 genes for the tumor specimens. We detected adenomatous polyposis coli E1538Ifs∗5, KRAS G12D, NF1 R652C, loss of SMAD4, TP53 R175H, IRF2 p.R82S, TCF7L2 p.A418Tfs∗14, and SMAD4 p.L43F in this patient. LESSONS: We reported serial mutations in key genes responsible for initiation and progression of colorectal cancer from a patient with Gardner syndrome.

Adipocyte-rich CTNNB1-mutated Intramuscular Gardner Fibroma Progressing to Desmoid Fibromatosis.

Gardner fibroma (GF) is a benign soft-tissue tumor that is associated with Gardner syndrome and can progress to, or co-occur with, desmoid fibromatosis (DF). Herein, we report a unique case of an 11-year-old boy who presented with a rapidly growing soft-tissue mass after biopsy of a stable fat-rich lesion present in the calf muscles since infancy, with Magnetic resonance imaging findings suggesting an intramuscular adipocytic tumor. The resection showed GF and DF. DF arising from a preexisting GF (the so-called "GF-DF sequence") is a well-documented phenomenon. Although immunohistochemistry was negative for nuclear ß-catenin expression, a CTTNB1 S45F mutation, which has been associated with aggressive behavior in DF, was identified in both components using a next-generation sequencing-based molecular assay. This is the first time a mutation in CTNNB1 has been identified in GF and the GF-DF sequence, thus expanding our knowledge of the molecular pathogenesis of the GF-DF sequence and highlighting the role of molecular testing in pediatric soft-tissue tumors. The histologic findings of an adipocyte-rich intramuscular GF also are unique, expanding the morphological spectrum of GF and adding GF to the differential diagnosis of intramuscular lesions with an adipocytic component.

A novel large deletion in the APC gene associated with Gardner syndrome in a Chinese family.

INTRODUCTION: Gardner syndrome is a hereditary disease characterized by familial adenomatous polyposis (FAP), accompanied by soft tissue tumors. MATERIAL AND METHODS: a Chinese FAP family was enrolled and followed-up for three years. RESULTS: a novel large germline fragment deletion (EX10_16DEL) of the adenomatous polyposis coli (APC) gene was identified by multiplex ligation-dependent probe amplification (MLPA). An unexpected abdominal tumor grew two years after a subtotal colectomy of the proband. The immunohistochemistry study of the abdominal tumor showed SMA(focal+), calponin(+), ß-catenin(nucleus+) and CD34(focal+), CD117(-), which was consistent with a desmoid tumor. CONCLUSION: when a FAP related desmoid tumor appears, the possibility of Gardner syndrome should be considered. This is the first largest deletion of the APC gene in the Chinese population associated with Gardner syndrome.

Gardner syndrome with giant abdominal desmoid tumor during pregnancy: a case report.

BACKGROUND: Gardner syndrome is a subtype of familial adenomatous polyposis (FAP), characterized by a combination of adenomatous intestinal polyps and extracolonic lesions such as multiple osteomas, dental abnormalities, and soft tissue tumors. Although 12% of patients with intestinal polyposis of FAP may occur intra-abdominal desmoid tumors, pregnancy complicating with giant abdominal desmoid tumors is a relatively rare case. CASE PRESENTATION: A 28-year-old pregnant woman was diagnosed with Gardner syndrome in whom an intra-abdominal tumor was found a year after undergoing a laparoscopic total colectomy due to family adenomatous polyposis. At 32 weeks' gestation, she presented to our department for the third time complaining upper abdominal pain caused by the giant abdominal mass about 21 × 12 cm2 in size. After multidisciplinary consultation and discussion, the decision of fetal preservation treatment was made. After the delivery of a baby girl, abdominal mass resection was performed, and pathological examination revealed a fibrous adenoma. The patient was discharged after a week and was uneventful in the follow-up for half a year. CONCLUSIONS: Gardner syndrome is characterized by typical syndrome including family adenomatous polyposis and extra-intestinal tissue tumor. Were desmoid tumors rarely as large as fetus and local aggressively. In our case, we selected surgery to remove the intra-abdominal desmoid tumor after the natural delivery of the fetus and no abnormalities were observed during the 6 months follow-up. Women during pregnancy have an increased risk for the development of desmoid tumors, likely with the sex hormone to be one of the triggers. Therefore, we suggested that when a patient with Gardner syndrome desire to conceive again, they should go to the hospital for a regular review at least once every 3 months.

Genodermatoses with malignant potential.

The hereditary nature of some forms of cancer was recognized long ago. Over time, recognition of associated findings led to the delineation of numerous hereditary cancer syndromes. Many of these syndromes also have cutaneous manifestations, the recognition of which can lead to their early identification. Recognition of these syndromes allows vigilant surveillance and preemptive treatment, which can dramatically impact the risks of morbidity and mortality for affected patients. The rise of rapid and accurate genetic testing now allows the early identification of asymptomatic at risk family members so that monitoring can be initiated as early as possible. The dermatologist plays a critical role in early identification of these syndromes and, in many cases, their treatment. This review summarizes many known hereditary cancer syndromes with cutaneous findings, their etiology, identification, evaluation, and management. Importantly, this is an ever evolving topic and new findings and syndromes will continue to be recognized. The dermatologist must be always alert to ensure they are detected.

Nuchal-type Fibroma: Single-Center Experience and Systematic Literature Review.

BACKGROUND: Nuchal-type fibroma is a rare benign tumor arising from the connective tissue. Our aim was to present our experience via two cases of this tumor and a comprehensive review of the literature. PATIENTS AND METHODS: We report a case of a 23-year-old female with a mass located in the posterior neck and the upper back and a case of a 50-year-old male with a mass located in the posterior neck, which were proved to be nuchal-type fibromas in the histopathological examination. We also searched the PubMed/Medline database for published cases of nuchal-type fibromas. RESULTS AND DISCUSSION: Nuchal-type fibroma is a rare benign tumor arising from the connective tissue, usually in the posterior neck, which affects different ages, with most patients being male. It is a poorly circumscribed tumor consisting of hypocellular, thick, dense and haphazardly arranged collagen bundles with entrapped adipocytes, nerve fibers and muscle fascicles and a few scattered spindle cells, which are CD34 positive. Its excision is curative, and the recurrence risk is generally low. However, patients with Gardner's syndrome may experience recurrence more frequently. CONCLUSION: Nuchal-type fibroma should be included in the differential diagnosis of subcutaneous, soft-tissue masses, especially when these involve the posterior neck.