{"paper_id":"508f713b-e7d3-4cc0-923a-bc1a4c852ea5","body_text":"Journal of Cutaneous and Aesthetic Surgery • Article in Press | 1\nis is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-Share Alike 4.0 License, which allows others \nto remix, transform, and build upon the work non-commercially, as long as the author is credited and the new creations are licensed under the identical terms.\n©2026 Published by Scientific Scholar on behalf of Journal of Cutaneous and Aesthetic Surgery\nCase Report\nFrom dormancy to diagnosis: A subcutaneous cyst \ntriggered by pregnancy\n Sunayana Misra1 , Md Ali Osama2 , Lipakshi Lakhiani1, Tarun Mittal3, Shashi Dhawan1\n1Department of Histopathology, Sir Gangaram Hospital, 2Department of Pathology, All India Institute of Medical Sciences, 3Department of General and \nLaparoscopic Surgery, Sir Gangaram Hospital, New Delhi, India.\n *Corresponding author: \nShashi Dhawan, \nDepartment of Histopathology, \nSir Gangaram Hospital, \nNew Delhi, India.\nshashi.dhawan@gmail.com\nReceived: 07 October 2025  \nAccepted: 08 May 2026  \nEPub Ahead of Print: 09 July 2026 \nPublished:\nDOI \n10.25259/JCAS_264_2025\nQuick Response Code:\nINTRODUCTION\nCutaneous ciliated cysts (CCC) of Müllerian origin represent rare lesions predominantly \noccurring in the lower extremities of women.  ey are hypothesized to originate from ectopic \nMüllerian rests that become activated during periods of hormonal stimulation such as puberty or \npregnancy.1 We present a case of a subcutaneous ciliated Müllerian cyst in the thigh of a young \nwoman with a temporal relationship to pregnancy, providing further evidence for the hormonal \nactivation hypothesis in the pathogenesis of these lesions.\nCASE REPORT \nA 22-year-old woman presented with a solitary, 3.5 cm, freely mobile soft tissue mass in the left  \nthigh [ Figure 1 ].  ere was no history of trauma, pain, tenderness, or overlying skin changes. \nHer past medical history was unremarkable.  e patient had an uneventful pregnancy 3 months \nbefore noticing the lesion, after which it gradually increased in size to its current dimensions. \nSurgical exploration revealed a subcutaneous cystic mass with no skin connection, which was \nfully excised. Gross examination revealed a tan-brown collapsed unilocular cyst with a 0.1 cm \nthick wall and smooth, glistening inner lining. Histological sections demonstrated a cystic lesion \nwith a fibrocollagenous wall exhibiting papillary folds forming focal finger-like projections \n[Figure 2 a and b].  e lining was composed of bland ciliated cuboidal to columnar epithelium \nwith focal pseudostratification [ Figure 2c]. Occasional cells with round nuclei and perinuclear \nclearing were observed at the base of the epithelium, reminiscent of the peg cells characteristic \nof fallopian tube epithelium [Figure 2d].  e cyst wall lacked smooth muscle, cartilage, mucous \nABSTRACT\nCutaneous ciliated Müllerian cysts are rare, hormonally responsive lesions typically occurring in women’s lower \nlimbs. We report a case of a 22-year-old woman who developed a subcutaneous thigh cyst shortly after pregnancy. \nHistology and immunohistochemistry confirmed Müllerian origin.  e lesion was completely excised, with no \nrecurrence at 1 year. is case reinforces the role of hormonal triggers, particularly pregnancy, in the activation of \ndormant Müllerian rests.\nKeywords: Cutaneous ciliated cysts, Müllerian, Pregnancy\nhttps://jcasonline.com/\nJournal of Cutaneous and Aesthetic \nSurgery\nArticle in Press\n\n\nMisra, et al.: Ciliated cutaneous Mullerian cyst\nJournal of Cutaneous and Aesthetic Surgery • Article in Press | 2\nglands, or adnexal structures. Immunohistochemical (IHC) \nrevealed that the lining epithelial cells were positive for pan-\ncytokeratin (AE1/AE3), estrogen receptor (ER), progesterone \nreceptor (PR), PAX-8, and WT1, supporting a Müllerian \norigin of the cyst [Figure 2e-g]. Based on the histopathological \nand IHC findings, a diagnosis of cutaneous Müllerian cyst \nwas established.  e patient remains asymptomatic 1  year \nfollowing complete surgical excision of the lesion.\nDISCUSSION\nCCC are rare, benign subcutaneous lesions initially reported \nby Hess in 1890 and later formally designated so by Farmer \nand Helwig in 1978.  ese cysts predominantly affect \nyoung women in their second to third decades of life and \ntypically present as solitary, asymptomatic, subcutaneous \nnodules with a predilection for the lower extremities. To \ndate, approximately 70  cases have been reported in the \nliterature, with the vast majority occurring in post-pubertal \nwomen.2  e pathogenesis of CCC is a subject of ongoing \ndebate, with two principal theories proposed. 1,2  e first \nhypothesis suggests that these cysts arise from heterotopic \nMüllerian tissue, explaining their female predilection and \nhormonal responsiveness. According to this theory, cells \nfrom the fimbrial end of the fallopian tube detach during \nearly embryogenesis and get incorporated into the lateral \nmesoderm where lower limb buds develop.  ese displaced \nMüllerian cells remain dormant until puberty or pregnancy, \nwhen hormonal stimulation triggers cystic fluid production \nand subsequent cyst formation.  e alternative hypothesis \nproposes ciliated metaplasia of eccrine sweat glands, possibly \nin response to inflammation or irritation of pluripotent \ncells. is theory may account for the rare occurrence of \nthese cysts in males and in atypical locations such as the \nscalp, fingers, and scapular area. 3,4 Recent literature has \nproposed a classification system to distinguish the two entities \npreviously grouped under the umbrella term “cutaneous \nciliated cysts” to acknowledge their different histogenetic \norigins. Cysts with positive ER/PR expression are designated \nas “ciliated cutaneous Müllerian cysts, ” while those negative \nfor these receptors but positive for carcinoembryonic antigen \n(CEA) are classified as “ciliated cutaneous eccrine cysts. ” \nHistologically, cutaneous Müllerian cysts are characterized \nby a lining of ciliated cuboidal to columnar epithelium \nthat may show pseudostratification, closely resembling \nfallopian tube epithelium.  e cyst wall typically consists of \nfibrocollagenous tissue that may form papillary projections \ninto the lumen. Importantly, the cyst wall lacks cutaneous \nappendages. IHC plays a crucial role in confirming the \nMüllerian origin of these cysts.  e epithelial lining typically \ndemonstrates positive staining for Paired Box Gene 8 (PAX-\nFigure  1: Clinical image showing a solitary, \nwell-circumscribed, freely mobile soft tissue \nmass located in the left thigh.\nFigure 2: (a) A collapsed unilocular cyst present in the deeper dermis \nand subcutaneous fat (short black arrows) with unremarkable epidermis \n(long black arrow) (Hematoxylin and Eosin, 40x). (b) Cyst wall (black \narrow) is thrown into multiple papillary foldings (Hematoxylin and \nEosin, 100x). (c)  e lining epithelium is bland columnar with brush \nborder and cilia (black arrow, Hematoxylin and Eosin, 200x). (d) Few \ncells with prominent cytoplasmic vacuolations reminiscent of peg cells \nof the fallopian tube (short black arrows) (Hematoxylin and Eosin, \n400x). (e-g) Cyst lining epithelium showing positivity for PAX8, WT1, \nand estrogen receptor (Immunohistochemical stains, 100x).\n\nMisra, et al.: Ciliated cutaneous Mullerian cyst\nJournal of Cutaneous and Aesthetic Surgery • Article in Press | 3\n8) and WT1, transcription factors essential for Müllerian \nduct development along with ER and PR.  e epithelium \nalso expresses pan-cytokeratin while typically being negative \nfor CEA. On histopathology, the differential diagnosis for \na ciliated cutaneous Müllerian cyst includes cutaneous \nendosalpingiosis, which also features fallopian tube-like \nepithelium and is ER/PR positive. Clinically, endosalpingiosis \nis rare and typically presents as painful nodular lesions \nexclusively around the umbilicus, often occurring after \nsalpingectomy. Fabien-Dupuis et al.5 reported a rare case of \na Müllerian-type ciliated cyst in the thigh of a 16-year-old \ngirl, located in the subcutaneous soft tissue without a dermal \nconnection.  e cyst lining showed positivity for ER, PR, \nPAX-8, and WT1, supporting Müllerian differentiation and \nsuggesting the possibility of an ectopic Müllerian cyst. 5 e \npresent case exemplifies a classic presentation of a cutaneous \nMüllerian cyst, with its occurrence in a young woman, \nlocation in the thigh, temporal relationship to pregnancy, and \ncharacteristic IHC profile.  e treatment of choice is complete \nsurgical excision, which is curative with excellent prognosis \nand no reported recurrences.\nCONCLUSION\nCutaneous Müllerian cysts are rare benign lesions that \nshould be considered in the differential diagnosis of \nsubcutaneous cystic masses in young women, particularly \nwhen occurring in the lower extremities.  e temporal \nassociation with pregnancy in the present case supports \nthe hypothesis that hormonal stimulation may activate \ndormant ectopic Müllerian rests. Histopathological \nexamination supplemented by immunohistochemistry is \nessential for establishing the diagnosis and distinguishing \nthese lesions from other ciliated cutaneous cysts. Complete \nsurgical excision is curative and associated with an excellent \nprognosis.\nAuthors’ contributions:  Sunayana Misra: Writing of manuscript, \npreparation of figure panels, data collection and mansucript \napproval; Md Ali Osama:Writing of manuscript, preparation of \nfigure panels and mansucript approval; Lipakshi Lakhiani: Data \ncollection and mansucript approval; Tarun Mittal: Operating \nsurgeon and manuscript approval; Shashi Dhawan: Data collection \nand mansucript approval.\nEthical approval: Institutional review board approval is not \nrequired.\nDeclaration of patient consent:  e authors certify that they have \nobtained all appropriate patient consent forms. In the form, the patient \nhas given consent for their images and other clinical information to \nbe reported in the journal.  e patient understands that the patient’s \nnames and initials will not be published and due efforts will be made \nto conceal their identity, but anonymity cannot be guaranteed.\nFinancial support and sponsorship: Nil.\nConflicts of interest:  ere are no conflicts of interest.\nUse of artificial intelligence (AI)-assisted technology for \nmanuscript preparation:  e authors confirm that there was no \nuse of artificial intelligence (AI)-assisted technology for assisting \nin the writing or editing of the manuscript and no images were \nmanipulated using AI.\nREFERENCES\n1. Joehlin-Price AS, Huang JH, Brooks JS, \nScharschmidt TJ, Iwenofu OH. PAX-8 expression in \ncutaneous ciliated cysts: Evidence for müllerian origin. Am J \nDermatopathol 2014;36:167-70.\n2. Y alçin AC, Y alçin N, Çakmak Hİ, Bedir R. Cutaneous \nciliated cysts: 2 Case reports and review of literature. Am J \nDermatopathol 2024;46:774-80.\n3. Kim Y , Kim H.  e cutaneous ciliated cyst in young male:  e \npossibility of ciliated cutaneous eccrine cyst. Case Rep Med \n2015;2015:589831.\n4. Doğan G, İpek H, Metin M, Özkayar Ö, Afşarlar ÇE. Cutaneous \nciliated cyst in an unusual location: Between two scapulas. \nCase Rep Surg 2018;2018:5961913.\n5. Fabien-Dupuis C, Cooper B, Upperman J, Zhou S, \nShillingford N. Mullerian-type ciliated cyst of the thigh with \nPAX-8 and WT1 positivity: A  case report and review of the \nliterature. Case Rep Med 2016;2016:2487820.\nHow to cite this article: Misra S, Osama MA, Lakhiani L, Mittal T, \nDhawan S. From dormancy to diagnosis: A subcutaneous cyst triggered by \npregnancy. J Cutan Aesthet Surg. doi: 10.25259/JCAS_264_2025","source_license":"CC0","license_restricted":false}