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An Bras Dermatol 2017 Nov-Dec;92(6):836-837

Private Clinic - São Paulo (SP), Brazil.

Nevus sebaceous of Jadassohn is a congenital hamartoma that usually affects the scalp and face. Several benign or malignant neoplasias may develop in the lesion and the most common are trichoblastoma, syringocystadenoma papilliferum, and basal cell carcinoma. Trichilemmoma is a benign solid tumor originating from external sheath cells of pilosebaceous follicles. Read More

Am J Dermatopathol 2018 Feb;40(2):131-135

Department of Dermatology, College of Medicine, Kyung Hee University, Seoul, Korea.

Phacomatosis pigmentokeratotica is a recently identified disease characterized by the coexistence of an epidermal nevus with sebaceous differentiation arranged along Blaschko lines and a speckled lentiginous nevus showing a checkerboard pattern, mostly in association with various extracutaneous defects. A 52-year-old man presented with asymptomatic ulcerative plaque on his left side of perioral area. A 2 × 2-cm-sized fleshy colored ulceration on his left perioral area was consistent with basal cell carcinoma with nevus sebaceous. Read More

Arch Craniofac Surg 2017 Mar 25;18(1):46-49. Epub 2017 Mar 25.

Department of Pathology, Busan-Baik Hospital, Inje University School of Medicine, Busan, Korea.

Nevus sebaceus is a hamartoma of the sebaceous gland that occurs congenitally, from which various secondary tumors can arise with a prevalence of 5%-6%. Benign neoplasms commonly arise from nevus sebaceous, but they have a very low malignant potential. Two neoplasms may occasionally arise within the same lesion, but it is rare for three or more neoplasms to occur in a nevus sebaceus simultaneously. Read More

Ann Saudi Med 2017 May-Jun;37(3):240-244

Lenah Alwatban, Department of Dermatology,, MBC 104, King Faisal Specialist Hospital and Research Centre,, PO Box 3354 Riyadh 11211,, Saudi Arabia, T: +966569450282 ORCID: http://orcid.org/0000-0002-0624-9910.

Background: Xeroderma pigmentosum (XP) is a rare autosomal recessive disorder caused by defective DNA repair that results in extreme sensitivity to ultraviolet (UV) rays. Depending on the type of XP, the disease may affect the skin, eyes and nervous system.

Objectives: Describe the dermatologic manifestations in patients suffering from XP. Read More

Actas Dermosifiliogr 2017 11 11;108(9):863-864. Epub 2017 May 11.

Servicio de Anatomía Patológica, Hospital General de Ciudad Real, Ciudad Real, España.

J Am Acad Dermatol 2017 Feb;76(2S1):S22-S24

Melanoma and Skin Cancer Unit, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile; Department of Pathology, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile.

Ophthalmic Plast Reconstr Surg 2017 Jul/Aug;33(4):233-236

*Ocular Oncology Service and †Department of Ophthalmic Pathology, Wills Eye Hospital, Thomas Jefferson University, Philadelphia, Pennsylvania, U.S.A.

Introduction: Cutaneous horn of the eyelid is uncommon. The authors evaluate the features of benign, premalignant, and malignant tumors at the base of cutaneous horn of the eyelid.

Objective: To describe the clinical and histopathologic features of cutaneous horn of the eyelid. Read More

J Cutan Pathol 2017 Jan 21;44(1):93-97. Epub 2016 Oct 21.

Department of Dermatology, Tufts Medical Center, Boston, MA, USA.

Trichilemmomas are benign cutaneous proliferations derived from the outer root sheath of the hair follicle. They most often occur on the head and neck region and show a female predominance. When multiple, they are associated with Cowden syndrome (CS), a rare disorder due to an autosomal dominant germline mutation in PTEN (phosphatase and tensin homolog on chromosome 10), a tumor suppressor gene. Read More

J Cutan Pathol 2017 Jan 20;44(1):79-82. Epub 2016 Oct 20.

Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, USA.

Cowden syndrome (CS) is an uncommon autosomal dominant multiorgan/system genodermatosis. It is characterized by the development of multiple hamartomas of endodermal, mesodermal and ectodermal origin, an increased lifetime risk of breast, thyroid, endometrial and other cancers and an identifiable germline mutation. Mucocutaneous hamartomas are the most common lesions seen and mainly include facial trichilemmomas, oral mucosal papillomas and benign acral keratoses. Read More

J Biol Regul Homeost Agents 2016 Apr-Jun;30(2 Suppl 2):17-20

Department of Medical 1Department of Pathology, Division of Dermatopathology, University of Virginia Health System, Charlottesville, Virginia.

Trichilemmoma and trichoblastoma are benign adnexal neoplasms derived from the hair follicle unit. While trichilemmomas are closely associated with the epidermis, trichoblastomas are found within the dermis and subcutaneous tissue. Both tumors have been reported to arise within nevus sebaceus of Jadassohn (NSJ). Read More

J Pediatr Health Care 2016 Sep-Oct;30(5):491-4. Epub 2016 Jun 29.

J Cutan Pathol 2016 Aug 10;43(8):649-56. Epub 2016 Jun 10.

Department of Pathology, University of Arkansas for Medical Sciences, Little Rock, AR, USA.

Sebaceous carcinoma is a rare but serious malignancy that may be difficult to diagnose when poorly differentiated. Other epithelial tumors with clear cell change may mimic sebaceous carcinoma. Few useful or specific immunohistochemical markers for sebaceous differentiation are available. Read More

J Cutan Pathol 2016 Jun 15;43(6):535-537. Epub 2016 Apr 15.

Department of pathology, Hospital Clínico Universitario, University of Valencia, Valencia, Spain.

Desmoplastic trichilemmoma (DT), the pseudomalignant variant of conventional trichilemmoma described by Hunt et al in 1990, displays a superficial lobular growth pattern of glycogen-rich cells with peripheral nuclear palisading surrounded by a thickened basement membrane. DT differs from its conventional counterpart by showing a central hyalinized area with epithelial cords and strands mimicking invasive carcinoma. We report a case that fully satisfies the criteria for DT and, in addition, shows an extensive melanocytic cell component and prominent melanin deposition. Read More

An Bras Dermatol 2015 Nov-Dec;90(6):780-96; quiz 797-8

Centro Hospitalar Universitário de Coimbra, Coimbra, Portugal.

Benign follicular tumors comprise a large and heterogeneous group of neoplasms that share a common histogenesis and display morphological features resembling one or several portions of the normal hair follicle, or recapitulate part of its embryological development. Most cases present it as clinically nondescript single lesions and essentially of dermatological relevance. Occasionally, however, these lesions be multiple and represent a cutaneous marker of complex syndromes associated with an increased risk of visceral neoplasms. Read More

Am J Dermatopathol 2015 Dec;37(12):885-91

Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, Los Angeles, CA.

Initial investigations reported GATA3 to be a sensitive and relatively specific marker for mammary and urothelial carcinomas. Recently, GATA3 expression has been described in several other epithelial tumors. However, there has been only limited investigation of GATA3 expression in cutaneous epithelial tumors. Read More

Cutis 2015 Aug;96(2):81, 104-6

Department of Dermatology, Saint Louis University, 4th Floor, Room 402, 1755 S Grand Blvd, St Louis, MO 63104, USA.

J Dermatol 2016 Feb 12;43(2):175-80. Epub 2015 Sep 12.

Department of Dermatology, National Taiwan University Hospital and College of Medicine, Taipei, Taiwan.

Nevus sebaceus is frequently associated with the development of secondary neoplasms. Incidences of malignant transformation vary among different reports and few data is available regarding Asian populations. We aimed to determine the characteristics of secondary tumors developing from nevus sebaceus in a Taiwanese population and to review the published work. Read More

Dermatol Pract Concept 2015 Apr 30;5(2):57-9. Epub 2015 Apr 30.

School of Medicine, The University of Queensland, Australia.

A case of trichilemmoma in continuity with a pigmented basal cell carcinoma is presented with dermatoscopy and dermatopathology. The distinction between the two lesions was evident dermatoscopically and was confirmed dermatopathologically. While trichilemmoma has been reported in association with basal cell carcinoma and dermatoscopy images of four previous cases of trichilemmoma have been published, no previous dermatoscopy image has been published of trichilemmoma associated with basal cell carcinoma. Read More

Int J Clin Exp Pathol 2015 1;8(3):3349-53. Epub 2015 Mar 1.

Department of Colorectal Surgery, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine Kongjiang Road 1665, Shanghai 200092, China.

Trichilemmoma is a rare type of benign cutaneous neoplasm, which derives from outer sheath of hair follicle. It barely develops malignant progression and has rarely been reported in anal cancer. In this article, we report a case of a 73-year-old woman who presented to the outer-patient department with complaints of a ruptured and longstanding anal phyma. Read More

Ophthalmic Plast Reconstr Surg 2016 Jan-Feb;32(1):e9-e12

*Department of Ophthalmology, Harvard Medical School; †David G. Cogan Laboratory of Ophthalmic Pathology, Massachusetts Eye & Ear Infirmary, Boston, Massachusetts, U.S.A.; ‡Department of Ophthalmic Pathology, CBLPath, Inc., Rye Brook, New York, U.S.A.; §Oculoplastic & Orbital Service, Wills Eye Hospital, Thomas Jefferson University, Philadelphia, Pennsylvania, U.S.A.; ‖Department of Dermatology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, U.S.A.

A 16-year-old African American male, the youngest patient to date, presented with a well-circumscribed upper eyelid lesion. On excision, the dermal nodule was contiguous with the epidermis, displayed trichohyalin-like bodies in an expanded outer root sheath, and was composed chiefly of small cellular clusters separated by a prominent network of periodic acid Schiff -positive hyaline bands of basement membrane material. The tumor cells were positive for high molecular weight cytokeratins (CK) 5/6, CK14, and CK34βE12 and were negative for CK7, carcinoembryonic antigen and epithelial membrane antigen. Read More

J Cutan Pathol 2015 Sep 12;42(9):645-51. Epub 2015 May 12.

Department of Dermatology, University of Iowa, Iowa City, IA, USA.

Herein, we describe a 63-year-old male with multiple tumors arising within a nevus sebaceus on the posterior scalp. On histopathologic examination, four distinct tumors were identified: trichoblastoma, syringocystadenoma papilliferum, desmoplastic trichilemmoma and tumor of the follicular infundibulum (TFI). Within the TFI component of the nevus sebaceus, there was intracytoplasmic accumulation of eosinophilic keratin, as shown on pancytokeratin-stained sections, imparting a signet-ring appearance to the cells. Read More

J Eur Acad Dermatol Venereol 2016 Feb 30;30(2):299-301. Epub 2015 Jan 30.

Department of Dermatology, STD and Leprosy, All India Institute of Medical Sciences, Patna, Bihar, India.

Background: Trichilemmoma are benign adnexal neoplasm with follicular outer sheath differentiation. It usually appears as single or multiple papules that resembles colour of the surrounding skin. They are most commonly seen on the face particularly on the nose and cheek. Read More

An Bras Dermatol 2014 Sep-Oct;89(5):796-8

Trichilemmoma is a benign neoplasm from the outer sheath of the pilosebaceous follicle. Desmoplastic trichilemmoma, a rare variant, is histologically characterized by a central area of desmoplasia that can clinically mimic an invasive carcinoma, requiring histopathological examination to define the diagnosis. Read More

Indian J Dermatol 2014 Jul;59(4):334-8

Department of Dermatopathology, Tehran University of Medical Sciences, Tehran, Iran.

Background: Papillomatosis is a known histopathologic pattern usually seen in human papillomavirus (HPV) infection and verruca vulgaris is the typical example. This pattern is also detected in some other benign cutaneous lesions such as nevus sebaceous (NS), seborrheic keratosis (SK), trichilemmoma (TL) and inverted follicular keratosis (IFK). The association between papillomatous lesions and HPV infection is questionable. Read More

Br J Dermatol 2014 Nov 30;171(5):1073-7. Epub 2014 Sep 30.

Department of Pathology, National Taiwan University Hospital, Taipei, Taiwan; Graduate Institute of Pathology, College of Medicine, National Taiwan University, Taipei, Taiwan.

Background: Trichilemmoma is a benign follicular epithelial tumour exhibiting outer root sheath differentiation. It is associated with Cowden syndrome and naevus sebaceus (NS), but the pathogenesis of sporadic tumours is poorly understood. Recently, NS was found to be caused by postzygotic HRAS or KRAS mutations. Read More

Ophthalmic Plast Reconstr Surg 2014 Sep-Oct;30(5):e136-8

Ross Eye Institute, Buffalo, New York, U.S.A.

Desmoplastic trichilemmomas (DTs) are a rare variant of trichilemmomas first described in 1985. Since then, 11 cases involving the eyelid have been reported. Two cases of this study raise this total to 13. Read More

J Cutan Pathol 2014 Jun 2;41(6):509-12. Epub 2014 Apr 2.

Department of Pathology, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Tao-Yuan, Taiwan.

Nevus sebaceus is known to have the potential to develop into various secondary tumors. We observed a sebaceoma arising from a nevus sebaceus excised from the left cheek of a 51-year-old woman. This sebaceoma showed desmoplastic change similar to that observed in desmoplastic trichoepithelioma and desmoplastic trichilemmoma. Read More

Am J Dermatopathol 2013 Aug;35(6):637-40

Department of Pathology, Ohio State University, Wexner Medical Center, Columbus, OH 43210, USA.

Trichilemmomas and mucocutaneous papillomatous papules are associated with Cowden syndrome (CS). Germline Phosphatase and tensin homolog (PTEN) mutations have been identified in 34% to 80% of those meeting clinical criteria for CS. PTEN expression has not been well evaluated in large numbers of trichilemmoma. Read More

Arq Bras Endocrinol Metabol 2012 Nov;56(8):592-6

Unidade de Tireoide, Laboratório de Endocrinologia Celular e Molecular, Faculdade de Medicina da Universidade de São Paulo, São Paulo, SP, Brazil.

Cowden syndrome is characterized by hamartomatous polyps, trichilemmomas, increased risk of developing neoplasms, and is associated with germline mutations in the PTEN gene. We searched for germline mutations in PTEN in a 49-year-old female patient who presented trichilemmoma with previous history of breast carcinoma, and thyroidectomy for a thyroid nodule. We also searched for somatic mutations in breast and thyroid tumoral tissues. Read More

Dermatol Surg 2012 Nov 17;38(11):1867-71. Epub 2012 Jul 17.

Division of Dermatology, Department of Medicine, University of California at San Diego, CA, USA.

Head Neck Pathol 2012 Dec 6;6(4):492-5. Epub 2012 Jun 6.

Department of Pathology, Hospital Universitario de Fuenlabrada, Camino del Molino 2, 28942, Fuenlabrada, Madrid, Spain.

Trichilemmoma is a benign cutaneous epithelial tumor with differentiation towards cells of the outer hair root sheath and usually presents as a small papule on the face of middle-aged or older adults. We herein report three cases of trichilemmoma located in the nasal vestibule, including two of the conventional type and one of the desmoplastic variant. To our knowledge, only one case of trichilemmoma arising in the nasal vestibule has been previously reported. Read More

J Cutan Pathol 2012 May 5;39(5):493-9. Epub 2012 Apr 5.

Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030-4009, USA.

Background: Trichilemmoma (TL) can occur as a solitary sporadic lesion usually on the face or as multiple facial lesions almost invariably associated with Cowden syndrome (CS). CS is a multisystem disorder caused by a germline inactivating mutation in PTEN (10q23.31), a tumor suppressor gene. Read More

J Maxillofac Oral Surg 2011 Mar 25;10(1):71-3. Epub 2010 Nov 25.

Trichilemmoma is a hamartomatous proliferation arising from cells of hair follicle. Its desmoplastic variant simulates an invasive carcinoma. In this tumor, the cell of origin seems to be located in the superficial level of the hair follicle just below the basement membrane at the sebaceous gland level. Read More

Dermatol Surg 2011 Dec 27;37(12):1806-10. Epub 2011 Sep 27.

Institute of Dermatology, Chinese Academy of Medical Sciences, Peking Union Medical College, Nanjing, Jiangsu Province, China.

J Med Assoc Thai 2010 Aug;93(8):978-91

Department of Pathology, Faculty of Medicine, Siriraj Hospital, Mahidol University Bangkok, Thailand.

Background: Sebaceous neoplasms are adnexal neoplasms that contain a varying number ofsebocytes, i.e. large cells with lipid-laden vacuolated cytoplasm, soap-bubble in appearance, and crenate nuclei. Read More

J Cutan Pathol 2010 Apr;37(4):403-10

Department of Pathology and Laboratory Medicine, Medical College of Wisconsin, Milwaukee, WI, USA.

The distinction of metastatic carcinomas to the skin from poorly differentiated primary cutaneous carcinomas and sometimes primary benign adnexal tumors can pose a significant diagnostic challenge. The purpose of this study was to evaluate the role of p63 and podoplanin (D2-40) immunoreactivity for separating primary skin tumors vs. cutaneous metastases of carcinomas from internal organs. Read More

Pathologica 2009 Jun;101(3):133-4

Dermatology Department, Habib Thameur Hospital, Tunis, Tunisia.

Trichilemmoma is a benign cutaneous tumor that shows characteristics of differentiation similar to the outer hair sheath. We report the case of a woman presenting with a nodular tender mass of the back that was diagnosed as an isolated trichilemmoma. Several lines of evidence suggest that trichilemmoma should be considered in the differential diagnosis of any indistinct facial papule. Read More

Am J Dermatopathol 2009 Oct;31(7):658-63

Department of Pathology, Siriraj Hospital, Mahidol University, Bangkok, Thailand.

Nevus sebaceous of Jadassohn (SNJ) is a congenital, hamartoma of multiple skin structures and may classically evolve through several stages of maturation. Many neoplasms have been reported to arise in association with SNJ, most commonly trichoblastoma and syringocystadenoma papilliferum. The coexistence of 3 or more tumors arising simultaneously within 1 lesion of SNJ is very rare. Read More

J Cutan Pathol 2010 Jan 13;37(1):75-80. Epub 2009 Jul 13.

Department of Dermatology, Wayne State University, Dearborn, MI, USA.

Background: It is hypothesized that trichilemmomas are 'burned out' verrucae. By performing in situ hybridization using HPV type-specific probes, we explored this concept.

Methods: Verrucae vulgaris and plantaris were positive controls, and inverted follicular keratoses (IFKs) were negative controls. Read More

J Cutan Pathol 2009 Jan;36(1):89-102

Department of Pathology, Hospital Universitario de Fuenlabrada, Fuenlabrada, Madrid, Spain.

Over the past few years, a growing number of cutaneous tumors expressing CD34 is being reported. The list contains benign and malignant neoplasms as well as reactive and hamartomatous lesions of diverse lineages of differentiation, including fibroblastic, myofibroblastic, fibrohistiocytic, vascular, neural, adipocytic, smooth muscle, hematopoietic, melanocytic and epithelial. The more frequent diagnostic difficulties are found in spindle cell proliferations, mainly in those of the fibrocytic lineage. Read More

J Cutan Pathol 2008 Dec;35(12):1079-92

Department of Pathology, Hospital Universitario de Fuenlabrada, Fuenlabrada, Madrid, Spain.

Over the past few years, a growing number of cutaneous tumors expressing CD34 is being reported. The list contains benign and malignant neoplasms as well as reactive and hamartomatous lesions of diverse lineages of differentiation, including fibroblastic, myofibroblastic, fibrohistiocytic, vascular, neural, adipocytic, smooth muscle, hematopoietic, melanocytic and epithelial. The more frequent diagnostic difficulties are found in spindle cell proliferations, mainly in those of the fibrocytic lineage. Read More

World J Gastroenterol 2008 Oct;14(37):5755-9

Tohoku University Graduate School of Medicine, 1-1 Seiryo, Aoba, Sendai 980-8574, Japan.

Cowden's disease, one of the several hamartoma syndromes, is characterized by hyperplastic lesions and hamartomas distributed in the whole body. About thirty percent of patients with Cowden's disease have been reported to be complicated by malignant tumors. Based on the criteria of the International Cowden Consortium, this disease is mainly diagnosed as trichilemmoma of the face and oral mucosal papillomatosis. Read More

Ann Dermatol 2008 Sep 30;20(3):157-61. Epub 2008 Sep 30.

Department of Dermatology, College of Medicine, Dong-A University, Busan, Korea.

Trichilemmal carcinoma is a cutaneous adnexal tumor originating from the outer root sheath of hair follicle, and it was first described by Headington in 1976. Clinically, it usually occurs as an asymptomatic solitary papule, nodule or mass on the face or scalp. This neoplasm is a malignant counterpart of trichilemmoma, and it has been reported in the literature as trichilemmal carcinoma, tricholemmal carcinoma, malignant trichilemmoma, and tricholemmocarcinoma. Read More

Eur J Dermatol 2008 Sep-Oct;18(5):518-23. Epub 2008 Aug 8.

Department of Dermatology, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan.

Nestin, a marker of neural stem cells, is expressed in the stem cells of the mouse hair follicle. The nestin-expressing hair follicle stem cells give rise to the outer-root sheath. Nestin-expressing hair follicle stem cells that are negative for the keratinocyte marker keratin 15 (K15) can differentiate into neurons, glia, keratinocytes, smooth muscle cells, and melanocytes in vitro. Read More

In Vivo 2006 Sep-Oct;20(5):583-5

Department of Dermatology, Mie University Graduate School of Medicine, 2-174, Edobashi, Tsu, Mie 514-8507, Japan.

An immunohistochemical study of cytokeratins (CK) in a case of trichilemmal carcinoma (TLC). CK expression showed the presence of CK 1, 10, 14 and 17, suggesting that TLC differentiates toward follicular infundibulum. In a comparison of CK expression between TLC and trichilemmoma, the absence of CK 15 and 16 in TLC may be related to transformation from trichilemmoma to TLC. Read More

Zhongguo Ji Sheng Chong Xue Yu Ji Sheng Chong Bing Za Zhi 2005 Dec;23(6):428-31

Department of Pathology, Changzheng Hospital, Second Military Medical University, Shanghai 200003, China.

Objective: To discuss the relationship between infestation of Demodex folliculorum and facial epidermal neoplasm.

Methods: A retrospective analysis was made with the pathological data of 153 cases collected in the recent four years on facial basal cell carcinoma, squamous cell carcinoma, seborrheic keratosis and trichilemmoma. The infection rate of Demodex folliculorum in the four types of neoplasm was evaluated and the relationship between the infection rate and the location of neoplasm and age was analyzed by V2 test. Read More

Eur J Ophthalmol 2004 Nov-Dec;14(6):562-4

Bakirkoy Education and Research Hospital, Eye Clinic - Turkey.

Purpose: To report an upper eyelid mass which proved to be a desmoplastic trichilemmoma.

Methods: A 60-year-old man had a slowly enlarging upper eyelid mass. The tumor was excised. Read More

Br J Dermatol 2004 Jul;151(1):165-9

Department of Dermatology, Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-0012, Japan.

Background: Recently, the novel antimicrobial peptide named dermcidin (DCD) was reported in human eccrine sweat glands.

Objectives: We investigated the expression of DCD in a variety of cutaneous tumours in order to assess the usefulness of the monoclonal antibody (G-81), which recognizes a fragment of DCD.

Patients/methods: We studied the immunoreactivity of the G-81 antibody on 197 cutaneous tumours. Read More

Dermatol Surg 2004 Jul;30(7):1062-4

Department of Dermatology, St. Luke's-Roosevelt Hospital Center, New York, New York 10025, USA.

Background: Desmoplastic trichilemmoma is a rare pseudomalignant variant of trichilemmoma. It generally presents as a small papule on the face and is often clinically misdiagnosed as a basal cell carcinoma or verruca vulgaris. It is histologically similar to a trichilemmoma, but has a central area of desmoplasia that can mimic an invasive carcinoma. Read More

J Dermatol Sci 2003 Oct;33(1):17-21

Department of Dermatology, Teikyo University School of Medicine, 11-1, Kaga-2, Itabashi-ku, Tokyo 173-8605, Japan.

Background: Nevus sebaceus of Jadassohn (NSJ) is a complex hamartoma in which various kinds of secondary neoplastic or hyperplastic proliferations such as primitive follicular structure (PFS) may arise. Recently, cytokeratin (CK) 20 expressed cells in PFSs and trichoblastomas of NSJs were demonstrated.

Objective: To clarify the nature and relationship among these proliferations, those in other secondary neoplasms and precise CK distributions in such lesional epidermis are examined. Read More