Papillomavirus-infected keratinous cyst on the sole. A histologic, immunohistochemical, and electron microscopic study

Association of human papillomavirus infection with palmoplantar epidermal cysts in Korean patients

Human papillomavirus (HPV) infection can develop into many different kinds of diseases ranging from simple warts to carcinoma in situ. Some investigators have recently suggested that HPV infection could be closely related to palmoplantar epidermal cysts. The aim of this study was to determine the existence of HPV and its subtype in palmoplantar epidermal cysts of Korean patients. We investigated 13 cases of palmoplantar epidermal cysts by employing clinical, histopathological and immunohistochemical examinations. In addition, PCR was performed using HPV 57 and 60 type primers. Four of the 13 cases (30.8%) showed the distinct histopathological features of palmoplantar epidermal cysts such as parakeratosis, vacuolar structures and eosinophilic inclusion bodies and these 4 cases showed positive immunohistochemical staining reactions for HPV. PCR for HPV detected type 60-positive bands in 5 of the 13 cases (38.5%), which included the 4 cases that were positive for immunohistochemical staining. These results show that HPV is associated with some cases of palmoplantar epidermal cysts in Korean patients, suggesting that HPV may play a role in the pathogenesis of these cysts.

Recurrent 'sterile' verrucous cyst abscesses and epidermodysplasia verruciformis-like eruption associated with idiopathic CD4 lymphopenia

Rupture of follicular (epidermoid) cysts is believed to be the consequence of bacterial infection. We report a 24-year-old man with idiopathic CD4 lymphopenia and chronic Mycobacterium avium intracellulare infection who developed multiple, recurring painful abscesses over the distal extremities that increased in number and severity when systemic steroid and interferon-gamma treatment was instituted for interstitial lung disease. Cultures were consistently negative for microorganisms, but pathological examination revealed ruptured epidermoid cyst walls with human papillomavirus (HPV) viropathic changes (keratinocytes with perinuclear halos and abundant basophilic keratohyaline granules). Cutaneous examination showed numerous, widespread flat-topped papules and achromic macules over the extremities, head and neck. Nested polymerase chain reaction analysis for HPV DNA revealed that the abscess-related cyst walls harboured epidermodysplasia verruciformis (EV)-associated HPV types 20, 24, alb-7 (AY013872) and 80. His cutaneous lesions harboured HPV types 3, 8 and 80. Similar to past reports, our patient developed an EV-like eruption in the setting of immunodeficiency. In this instance, EV-associated HPV infection of the follicular infundibular epithelium or pre-existing cysts in the setting of immunodeficiency may have led to cystic growth, rupture and subsequent painful inflammation.

Detection of human papillomavirus 60 in epidermal cysts of nonpalmoplantar location

Human papillomavirus (HPV) types 57 and 60 are associated with epidermal cysts of palmoplantar location (PPECs). Recently, there was a report of HPV 60 in a wart located in a nonpalmoplantar area as a possible precursor of a nonpalmoplantar epidermal cyst (NPPEC). There has been no study that has examined the presence and frequency of HPV in ordinary NPPECs. We reviewed 63 cases of epidermal cysts, including 59 NPPECs and 4 PPECs. After routine histopathologic review, polymerase chain reaction (PCR) of extracted DNA, sequencing of PCR products, and, finally, a homology search were undertaken. As a result, 9 of 63 (14.3%) cysts, including 6 of 59 NPPECs (10.2%), showed a positive reaction on PCR. By homology search after PCR, all were demonstrated as HPV 60. For NPPECs, no variables, including some histopathologic features, are significantly related to the presence of HPV 60 in univariate or multivariate analysis (P > 0.05).

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.

Verrucous cysts: histopathologic characterization and molecular detection of human papillomavirus-specific DNA

Verrucous cyst is an uncommon newly described benign epithelial cyst which may be associated with human papillomavirus infection. The purpose of this project was to study the clinicopathological features of verrucous cysts and to demonstrate human papillomavirus (HPV) by polymerase chain reaction (PCR) in these lesions. We have analyzed 5 examples of verrucous cysts: the age range of the patients was between 37-82 years and the most common locations were face and extremities. Clinically the lesions were interpreted as cyst (2), dermatofibroma (2) and basal-cell carcinoma (1). Histopathologic examination of the biopsy specimens showed in all cases an intradermal infundibular cyst lined by a papillated and/or digitated epithelium with focal prominent hypergranulosis and irregular keratohyalin granules. Furthermore, numerous whorls of keratinocytes (so-called squamous eddies) were present within the squamous areas of the hyperplastic epithelium of the cyst, morphologically reminiscent of inverted follicular keratosis. Architectural and cytological features of malignancy were not present. Sections of paraffin-embedded tissue of the 5 verrucous cysts and of 5 "conventional" follicular cysts, infundibular type, were investigated for the presence of HPV DNA sequences by PCR using consensus primers. In all 5 cases of verrucous cysts, HPV-specific DNA sequences were detected, whereas all follicular cysts, infundibular type, were negative. These results support the concept that verrucous cysts can be added to the large spectrum of HPV-induced cutaneous neoplasms. Further studies are needed to identify the specified HPV-type in these distinctive benign cystic proliferations.

Human papillomavirus in an epidermoid cyst of the sole in a non-Japanese patient

Several patients with an epidermoid cyst of the sole have recently been described in Japan. In these cases human papillomavirus was found in the wall and in the content of the cyst. We report the first documented case outside of Japan in which human papillomavirus has been demonstrated in an epidermoid cyst of the sole.