Multiple plantar epidermoid cysts harboring carcinoembryonic antigen and human papillomavirus DNA sequences

Trichilemmal Cysts With Divergent Ductal Differentiation: A Series of 4 Cases

ABSTRACT

Trichilemmal cysts are common clonal tumors with a predilection for the scalp. They are composed of an outer epithelial wall resembling the outer root sheath in the isthmus of the hair follicle and a central core of compact keratin. Sweat duct differentiation is exceptional with only one convincing case reported to date. Here, we sought to characterize the clinicopathological characteristics of sweat duct differentiation in trichilemmal cysts. We reviewed all cases of trichilemmal cyst diagnosed at our institution between 2008 and 2019. Ductal structures were found in 4 of 411 cases (0.97%). Subjects included 2 male and 2 female patients with a median age of 37.5 years (range 34-55). The ducts were lined by attenuated epithelial cells and immunoreactive for polyclonal carcinoembryonic antigen and cytokeratin 7. Ductal differentiation involved a median of 7.5% (range 1%-50%) of the cyst wall. All 4 cases were from the scalp and treated with local excision. No recurrence was identified with a median follow-up period of 1.5 years (range 1-12 years). In summary, sweat duct differentiation in trichilemmal cysts is rare but likely under recognized. Conceptually, we suggest it represents a type of divergent cellular differentiation within a clonal neoplasm rather than a retention cyst or hybrid cyst.

Verrucous pilar cysts infected with beta human papillomavirus

Epidermoid cysts with histopathologic features of human papillomavirus (HPV) infection have been previously reported and are commonly termed verrucous cysts. We report a series of eight histopathologically distinct verrucous pilar cysts, distinguished from traditional verrucous epidermoid cysts by trichilemmal keratinization, as well as two verrucous hybrid pilar-epidermoid cysts. These lesions contain characteristic stratified epithelial linings with abrupt transitions to compact eosinophilic keratin, as well as areas of papillomatosis, coarse intracytoplasmic keratohyalin granules, and vacuolar structures suggestive of HPV-induced cytopathic change. HPV-24, a β genus HPV species, was identified by degenerate polymerase chain reaction in DNA extracted from two of the lesions, and the presence of β-HPV E4 protein was confirmed by immunohistochemistry. HPV-60, the HPV species most commonly reported in verrucous epidermoid cysts, was not detected. Verrucous pilar cysts represent histopathologically and potentially etiologically distinct lesions which may be underrecognized.

Human papillomavirus molecular biology and disease association

Human papillomaviruses (HPVs) have evolved over millions of years to propagate themselves in a range of different animal species including humans. Viruses that have co‐evolved slowly in this way typically cause chronic inapparent infections, with virion production in the absence of apparent disease. This is the case for many Beta and Gamma HPV types. The Alpha papillomavirus types have however evolved immunoevasion strategies that allow them to cause persistent visible papillomas. These viruses activate the cell cycle as the infected epithelial cell differentiates in order to create a replication competent environment that allows viral genome amplification and packaging into infectious particles. This is mediated by the viral E6, E7, and E5 proteins. High‐risk E6 and E7 proteins differ from their low‐risk counterparts however in being able to drive cell cycle entry in the upper epithelial layers and also to stimulate cell proliferation in the basal and parabasal layers. Deregulated expression of these cell cycle regulators underlies neoplasia and the eventual progression to cancer in individuals who cannot resolve high‐risk HPV infection. Most work to date has focused on the study of high‐risk HPV types such as HPV 16 and 18, which has led to an understanding of the molecular pathways subverted by these viruses. Such approaches will lead to the development of better strategies for disease treatment, including targeted antivirals and immunotherapeutics. Priorities are now focused toward understanding HPV neoplasias at sites other than the cervix (e.g. tonsils, other transformation zones) and toward understanding the mechanisms by which low‐risk HPV types can sometimes give rise to papillomatosis and under certain situations even cancers. Copyright © 2015 John Wiley & Sons, Ltd.

Human papillomavirus infection and ultraviolet light exposure as epidermoid inclusion cyst risk factors in a patient with epidermodysplasia verruciformis?

Epidermoid inclusion cysts are common lesions with unclear etiology. We sought to examine evidence for human papillomavirus (HPV) infection and ultraviolet light (UV) exposure as risk factors in the formation of epidermoid inclusion cysts. We performed HPV typing of biopsied cysts with polymerase chain reaction for a patient with darkly-pigmented skin, epidermodysplasia verruciformis (EV) and more than 250 photodistributed cysts. HPV types 8 and 6 DNA was demonstrated within biopsy specimens of 3 cysts. In one biopsy specimen, abnormal keratinocytes bridging the follicular infundibulum were seen. We concluded that UV exposure and HPV viral infection may be risk factors for the formation of epidermoid inclusion cysts.

Melanoma in situ involving an epidermal inclusion (infundibular) cyst

Epidermal inclusion (infundibular) cysts are common tumors encountered in the practice of dermatology and dermatopathology. Although benign, numerous pathological processes, including benign and malignant tumors, inflammatory dermatoses, and certain infectious entities, have been reported to occur within the epithelial lining of infundibular cysts. We report a rare case of malignant melanoma in situ involving the epithelium of an epidermal inclusion cyst in contiguity with an adjacent malignant melanoma.

Human papillomavirus-associated plantar epidermoid cyst related to epidermoid metaplasia of the eccrine duct epithelium: a combined histological, immunohistochemical, DNA-DNA in situ hybridization and three-dimensional reconstruction analysis

BACKGROUND

We recently proposed that certain palmoplantar epidermoid cysts may be related to eccrine ducts and that human papillomavirus (HPV) 60 may play a role in their pathomechanism. However, the origin of palmoplantar epidermoid cysts is still controversial.

OBJECTIVES

To examine the contribution of eccrine ducts and HPV 60 in the development of epidermoid cysts.

METHODS

Five epidermoid cysts and four ridged warts that had developed on the soles of a patient were studied histologically, immunohistochemically and by DNA-DNA in situ hybridization. Using serial sections obtained from its entire body, a three-dimensional reconstruction (3DR) analysis was performed on the smallest cyst to analyse the relationship between the epidermoid cyst, eccrine duct and the overlying epidermis.

RESULTS

Histological and DNA-DNA in situ hybridization analyses demonstrated both homogeneous intracytoplasmic inclusion bodies pathognomonic for HPV 60 infection and HPV 60 DNA sequences not only in all of the epidermoid cysts and ridged warts but also in the acrosyringeal portion of an eccrine duct, with the dermal portion of which the smallest cyst had been revealed to connect by 3DR analysis. However, immunohistochemical analyses using antibodies against human carcinoembryonic antigen (CEA), involucrin and several cytokeratins (CKs) revealed that the immunoreactivity of the cyst was not identical to that of the eccrine dermal duct but was identical to that of suprabasal layers of the epidermis.

CONCLUSIONS

It was clearly demonstrated that an HPV 60-associated epidermoid cyst with immunoreactivities for CEA, involucrin and CKs which were identical to those of the epidermis connected with the eccrine dermal duct, supporting the idea that certain palmoplantar epidermoid cysts may develop following the epidermoid metaplasia of eccrine ducts with HPV 60 infection.

Human papillomavirus 57 identified in a plantar epidermoid cyst

We report a 23-year-old Japanese man who had plantar warts on the right sole, beneath one of which an epidermoid cyst developed. On microscopic examination, an acanthotic epidermis markedly invaginated into the underlying dermis, resulting in an open epidermoid cyst. Not only the polymerase chain reaction but also an in situ hybridization detected HPV 57 DNA in the cyst. HPV 60 is the only type of HPV that has been identified in epidermoid cysts. To our knowledge, this is the first case report of an epidermoid cyst, in which a different type of virus from HPV 60 was identified. Histological features of the cyst were also different those of HPV 60-associated epidermoid cysts.

Detection of human papillomaviruses and eccrine ducts in palmoplantar epidermoid cysts

Although epidermoid cysts of the palms and soles have long been assumed to develop following implantation of an epidermal fragment as a result of a penetrating injury, the pathogenic mechanism is still controversial, and the discovery of a more common aetiological agent is awaited. Clinical, histological, immunohistochemical and molecular biological studies were performed on 119 epidermoid cysts of palmoplantar location, in order to examine the role of the eccrine ducts, and human papillomavirus (HPV), in the pathogenesis of this disorder. Characteristic histological features were found, including intracytoplasmic eosinophilic bodies (ICB: in 14 cases, 12%) in the cyst wall, vacuolar structures (V: in 28 cases, 24%), or parakeratotic nuclei (P: in 85 cases, 71%) within the keratinous mass in the cyst cavity. Ductal structures suggesting eccrine ducts (E: in 63 cases, 53%) were also found in the cyst wall or in the cyst cavity. Either ductal structures or carcinoembryonic antigen expression (66 cases, 55%) were noted in a total of 73 cases (61%). Papillomavirus common antigens were detected in 36 cases (30%) showing one or more of the three distinct histological features, i.e. ICB, V and P. Subsequently, hybridization experiments to detect HPV DNA were performed in 47 cases, revealing an association between cysts showing ICB or V and the presence of HPV 60 DNA sequences. On the basis of our results, we propose that epidermoid cysts in the palmoplantar regions may develop from eccrine ducts, and that HPV and injury may play a role in their pathogenesis.