Expression of keratins (K10 and K17) in steatocystoma multiplex, eruptive vellus hair cysts, and epidermoid and trichilemmal cysts

Conditional Knockout of N-WASP Enhanced the Formation of Keratinizing Squamous Cell Carcinoma Induced by KRasG12D

Squamous cell carcinoma (SCC) is one of the most common forms of skin cancer in humans, and Neural Wiskott-Aldrich Syndrome Protein (N-WASP) plays a crucial role in epidermal homeostasis. To elucidate the role of N-WASP in skin cancer, we generated mice which expressed constitutively active KRas (KRasG12D) in keratinocytes with either homozygous (N-WASPKOG12D) or heterozygous (N-WASPHetG12D) N-WASP knockout upon Tamoxifen (TAM) injection. Both the N-WASPKOG12D and N-WASPHetG12D mice had similar body weights and no congenital malformations prior to the injection of TAM. Within 2 weeks of the injections, the N-WASPKOG12D mice exhibited significant reductions in weight coupled with visible tumors at numerous sites, unlike the N-WASPHetG12D mice, which had no visible tumors. We found that both sets of mice had oily, sticky skin and wet eyes 3 weeks after their exposure to TAM, indicating the overproduction of sebum/meibum. At 37 days post TAM injection, several notable observations were made. Tumors collected from the N-WASPKOG12D mice had small- to large-sized keratin pearls that were not observed in the N-WASPHetG12D mice. A Western blot and immunostaining analysis both highlighted significantly higher levels of expression of SCC markers, such as the cytokeratins 8, 17, 18, and 19 and TP63, in the tumors of the N-WASPKOG12D mice compared to those of the latter group. Furthermore, we noted increases in the expression levels of EGFR, P-ERK, GLUT1, P-mTOR, and P-4EBP in the N-WASPKOG12D mice, suggesting that the deletion of N-WASP in the keratinocytes enhanced KRas signaling and glucose uptake, resulting in aggressive tumor formation. Interestingly, a thickening of the epidermal layer within the esophagus and tongue was only observed in the N-WASPKOG12D mice. Immunostaining for PCNA emphasized a significantly higher number of PCNA-positive cells in the skin of the N-WASPKOG12D mice compared to their counterparts, implying that epidermal thickening and enhanced tumorigenesis are due to an increased proliferation of keratinocytes. Through our results, we have established that N-WASP plays a tumor-suppressive role in skin cancer.

Steatocystoma multiplex of the scrotum. Clinical case

Steatocystoma multiplex is a disorder of the pilosebaceous unit characterized by multiple sebum-containing dermal cysts. We report the case of a 64-year-old male presented with multiple skin-colored, partially hyperemic cystic located in the scrotum area. They were accompanied by an active inflammatory process in the form of pain, swelling, hyperemia. The lesion was present for about 1 month. Previously, this patient had diagnosed with multiple steatocystoma located in the hip area and received surgical treatment.

At present, such reports in the scientific databases are presented sporadically, therefore we report on multiple steatocystoma of the scrotal localization due to its rarity.

Expression of BMP4 and FOXN1 in orthokeratinized odontogenic cyst compared to odontogenic keratocyst suggests an epidermal phenotype

Odontogenic keratocysts (OKC) and orthokeratinized odontogenic cysts (OOC) are odontogenic cysts that share histological and immunohistochemical similarity with epidermal appendages and cutaneous cystic lesions despite exhibiting contrasting biological behavior. In epidermal appendages, BMP4 induces expression of FOXN1, which participates in terminal differentiation of keratinocytes and control of proliferation. We compared BMP4 and FOXN1 expression in OOC and OKC to investigate their role in the epithelial differentiation of these cysts. BMP4 and FOXN1 expression was assessed using immunohistochemistry in 20 primary sporadic OKC and compared to 16 OOC. BMP4 epithelial expression was detected in 81.25% OOC compared to 35% in OKC, while its expression in connective tissue was observed in 65% OKC and 75% OOC. FOXN1 was detected in 75% OOC vs. 30% OKC. The "triple positive" phenotype, i.e., BMP4 epithelial and connective tissue positivity and FOXN1 epithelial positivity, was seen in 56.25% OOC compared to 10% OKC. The greater expression of BMP4 and FOXN1 in OOC suggests greater activation of this pathway in OOC, which suggests a role in its more mature epithelium; it also resembles an epidermal phenotype.

Giant, Bleeding, and Ulcerating Proliferating Trichilemmal Cyst, With Delayed Treatment Due to Coronavirus Outbreak: A Case Report and Review of the Literature

We report a case of a large, ulcerating proliferating trichilemmal cyst in a 76-year-old woman, with clinical, radiological, macroscopic, and microscopic correlation. The outbreak of the Coronavirus pandemic delayed her treatment. We review the literature on proliferating trichilemmal cysts, which are relatively rare tumors, which, generally, are considered benign. However, we found a high rate of malign cases, which stresses the importance of rapid surgical excision and histological diagnosis. Even though our proband had delayed treatment, the tumor did not transform into a malignant form.

An alternative diagnostic method of eruptive vellus hair cysts: Report of a familial case with pruritus

Eruptive vellus hair cysts (EVHC) represent a developmental abnormality of vellus hair follicles. Up till now more than 150 cases of EVHC have been published in the literature, but it appears to be more common than recognized. The diagnostic hallmark is the presence of vellus hair shafts within the cystic space. Firstly to evaluate the potential benefit of new diagnostic method of EVHC using a dermatoscope and secondly to report a familial case of EVHC where females were only affected. Five women from the same family with a clinical diagnosis of EVHC were included in the study. The diagnosis of EVHC was confirmed by skin biopsy with histologic examination in four patients. New diagnostic approach of the cyst contents examination with using a handheld dermatoscope was performed in all patients. Numerous vellus hair shafts were detected on the images of the cysts content taken with dermatoscope and applying the above-mentioned method in all patients. We suggest that it seems possible to differentiate EVHC by using the dermatoscope, which appears to be simple, quick, and less time consuming.

Cutaneous Adnexal Cysts Revisited: What We Know and What We Think We Know

Cutaneous cysts have been classified by dermatopathologists in many different ways. Here, we propose a novel classification of cutaneous adnexal cysts according to their origin in the folliculosebaceous unit and the sweat glands. By examining the lining of the cystic structure, its origin can be easily identified. Epidermal cysts have an epithelial wall containing a granular layer with lamellar keratinization, indicating an infundibular origin. Tricholemmal cysts have an undulating epithelial wall with no granular layer and a compact keratinization, showing an isthmic origin. In steatocystoma, dermoid cyst, and folliculosebaceous hamartoma, the epithelial lining shows a crenulated appearance which is seen in the sebaceous duct. Hidrocystoma shows the characteristic cuboidal epithelial lining of sweat glands with decapitation secretion in its apocrine forms. The hair matrix cyst wall is composed of basaloid cells maturing to squamoid cells, as seen in the normal hair matrix and shadow cells in the lumen. Metabolizing acquired dioxin-induced skin hamartoma (MADISH) is a cystic lesion with lamellar keratinization, and no sebaceous glands. The classification proposed here aims to simplify the complexity of cutaneous adnexal cysts, and to facilitate a better understanding of the origin of cystic lesions of the skin.

An Unusual Case of Facial Steatocystoma Multiplex: A Clinicopathologic and Dermoscopic Report

Background

Steatocystoma multiplex is a benign skin disorder originating from the sebaceous and nevoid ducts. Commonly classified under hamartomas, they are distributed over the trunk, neck, axillae, and groin.

Methods

A 28-year-old male patient complained of multiple, asymptomatic skin-colored nodules over the face of 10-year duration. Clinical examination confirmed the historic findings of nontender, polysized, flesh-colored papules and nodules over the said distribution.

Results

On histopathology, a cyst was noted in the mid-dermis, lined by stratified squamous, agranular epithelium, which contained degenerated keratin. Nonpolarized dermoscopy showed a structureless, cream-colored area, and polarized dermoscopy revealed a distinctive, well-circumscribed, yellowish hue which was superimposed over the facial pseudoreticular pigmentary pattern. The findings were compatible with steatocystoma multiplex, and the patient was taken up for radiofrequency ablation.

Conclusion

Herein, we report a rare variant of steatocystoma multiplex limited to the face and scalp subjected to dermatoscopy and characteristic histological correlation. To the best of our knowledge and following a literature search, dermoscopic features of this condition have not been reported thus far.

Eruptive Vellus Hair Cyst: An Uncommon and Underdiagnosed Entity

Eruptive vellus hair cyst (EVHC) is a rare follicular developmental abnormality of the vellus hair follicles. They are usually seen in children, adolescents, or young adults and manifest as reddish-brown smooth papules most commonly involving the chest, limbs, and abdomen. An 18-year-old male presented with asymptomatic papules on the trunk and flexor aspect of both forearms for the past 2 years. There was no family history of similar lesions. His medical history was also not contributory. A clinical diagnosis of steatocystoma multiplex and chronic folliculitis was given, and a punch biopsy from the papule was performed and sent for histopathological examination. On microscopic examination, a final diagnosis of EVHC was rendered. The patient was advised topical treatment of retinoic acid cream (0.05%) for 6 months, and he is currently under follow-up period. Due to its rarity and resemblance to many similar entities, histopathological examination plays a major role in establishing a definite diagnosis and further proper management of the patient. We report this unusual case to generate awareness about this rarely diagnosed condition.

Case Series: A Kindred With Eruptive Vellus Hair Cysts and Systemic Features

Eruptive vellus hair cysts (EVHCs) often occur on the trunk and limbs. Facial involvement is uncommon. Autosomal dominant inheritance has been described, but associated extracutaneous anomalies have not. We describe a 4-patient kindred presenting with multiple facial EVHCs and an association of preauricular pits, lipomas, joint hypermobility, and cardiac defects. Histopathologic examination confirmed the diagnosis of EVHCs in 3 affected individuals. We propose that facial EVHCs may indicate the presence of an inherited autosomal dominant disorder with extracutaneous manifestations. Extracutaneous manifestations noted in the kindred have been sporadically described in association with steatocystoma multiplex (SM), a condition occasionally noted in the presence of EVHCs, further supporting an association between these disorders.

A Tale of Two Cysts: Steatocystoma Multiplex and Eruptive Vellus Hair Cysts—Two Case Reports and a Review of the Literature

Background. Steatocystoma multiplex (SM) and eruptive vellus hair cysts (EVHC) are uncommon benign tumors of the pilosebaceous unit. Both SM and EVHC are characterized by smooth, asymptomatic papules or nodules, most commonly presenting on the chest, limbs, and abdomen. Most cases of SM and EVHC are sporadic, although less common autosomal dominant inherited forms have been reported. Main Observation. In this report we present two cases of cutaneous cysts exhibiting characteristics of either SM or EVHC. Both patients presented with numerous 1-2 mm asymptomatic papules and responded well to surgical expression by incision and drainage (I&D). Conclusion. SM and EVHC are similar in clinical presentation and management. Previously reported “hybrid-type” tumors present strong evidence for a relationship between the two lesions pathologically. Due to potential similarity of EVHC and SM cyst contents, I&D and subsequent microscopic examination cannot definitely differentiate between EVHC, SM, and hybrid cysts.

Clinicopathological features and expression of four keratins (K10, K14, K17 and K19) in six cases of eruptive vellus hair cysts

Six cases of eruptive vellus hair cysts (EVHC) were evaluated for histopathology and the immunohistochemical profile of Ki-67 and four keratins (K10, K14, K17 and K19). The pathological hallmark of EVHC was the existence of vellus hair shafts within the cystic cavity, but atypical pathological changes included two or three cysts and a foreign-body granuloma in three cases. Our results demonstrate that atypical pathological changes are not uncommon in EVHC, and indicate that based on keratin expression, it is likely that EVHC is derived from the infrainfundibulum and sebaceous duct.

Eruptive vellus hair cyst presenting as asymptomatic follicular papules on extremities

Eruptive vellus hair cysts were first described in 1977. They usually appear as yellow to reddish-brown papules on the chest. Usual onset is between ages 17 and 24 years, but they may be congenital. Some believe that they may be inherited as an autosomal dominant disorder. Histologically the cyst has a stratified squamous epithelium and it contains laminated keratin and vellus hairs. They are felt to be caused by an abnormality at the infundibular level of the vellus hair. We present this because of this patient's unusual distribution of eruptive vellus hair cysts.

Steatocystoma multiplex-a rare genetic disorder: a case report and review of the literature

A 17 years old female presented with multiple asymptomatic cutaneous cysts all over body, sparing the head and neck region. The microscopic examination of the cysts showed the features of steatocystoma multiplex. This disorder, although it is asymptomatic, is a cosmetic threat to the patient. Only a few cases of the patients with an autosomal dominant mutation, who had keratin 17, have been reported. We are reporting here, a case of steatocystoma multiplex in a 17 years old female, along with its review of literature.

Familial eruptive vellus hair cysts

Eruptive vellus hairs cysts are benign papules consisting of small cysts containing multiple vellus hairs. An eruption commonly develops on the chest and sometimes the upper extremities. These papules are asymptomatic or rarely pruritic. Only a few cases of familial association have been described. We report the development of eruptive vellus hair cysts on the trunk of an 8- and 12-year-old sister and brother.

Eruptive vellus hair cysts: report of a new case with immunohistochemical study and literature review

Eruptive vellus hair cysts (EVHC) are rather uncommon lesions, of which 222 cases have been published in the literature. Their etiopathogenesis is poorly known. We report herein a new typical case of EVHC that was studied immunohistochemically. A 15-year-old male presented with a 4-year history of progressively developing small brown-gray papules on the trunk and extremities. Microscopically the lesions consisted of small epidermoid cysts containing vellus hairs. Immunohistochemically, the lesions expressed keratin 1/10, calretinin and p63 but no epithelial membrane antigen, filaggrin or androgen receptors. A review of the relevant literature shows that EVHC may be inherited or acquired and may be associated to other genodermatoses, namely sebocystomatosis. They could be due to hamartomatous follicular growth, to a trouble in infundibular keratinization leading to vellus hair follicle occlusion, or represent an example of acquired hamartoma. Although benign, this condition is difficult to treat.

Eruptive vellus hair cysts: a systematic review

We report the results of the first systematic review of the worldwide literature on eruptive vellus hair cysts (EVHC). It is likely that EVHC are less rare than it may appear from the scarcity of related publications in the literature. EVHC may be present at birth and may appear at any age, although they show a clear trend towards occurring during the first 3 decades of life. A strong clue to the heavy influence of genes on the occurrence of EVHC is provided by the numerous reports of families in whom two or more members were affected. EVHC lesions present clinically in a rather monomorphous fashion, i.e. round, dome-shaped, skin-colored, asymptomatic, soft-tender papules with a smooth surface and grouped or disseminated in a symmetric pattern. EVHC may affect any cutaneous area, even if the upper part of the body and some distribution patterns are particularly frequent and recognizable, i.e. cephalic, upper trunk around the midline, upper limb including axillae, and proximal lower limb. Such a distribution is likely not random and seems to grossly overlap with that of pilosebaceous and apocrine units. Like clinical morphology, the histologic features of EVHC papules are rather monomorphous, indeed, the diagnostic hallmark being the presence of vellus hair shafts within the cystic space. Peculiar subgroups (familial, late-onset, unilesional, and associated with steatocystoma multiplex) are also identified and discussed. In conclusion, EVHC are basically a cosmetic concern to patients but represent a chronic and difficult-to-treat condition. On the basis of our review, future studies are warranted, mainly concerning (i) further nosographic framing involving genetic and tissue analysis, (ii) implementation of non-invasive diagnostic procedures, and (iii) therapeutic trials of interventions shown to achieve some effectiveness.

Vellus hair cysts presenting as an atypical acneiform eruption

A 32-year-old male patient presented for 8 months an asymptomatic therapy-resistant acneiform eruption on his back and buttocks. Skin examination showed several inflammatory papules, which evolved to hyperpigmentation. At the same distribution non inflammatory papules, which resembled rice grains, were also observed. Light microscopy showed small keratin-filled cysts, with an epithelial multilayered wall, without granular layer. Keratin and some vellus hairs were identified inside the cyst, confirming the diagnosis of vellus hair cysts. Diagnosis of vellus hair cysts should be suspected in cases of multiple papules or therapy-resistant cases of acneiform eruptions.

A case of eruptive vellus hair cysts that developed on the labium major

Eruptive vellus hair cysts are asymptomatic, flesh-colored-to-bluish, 1-to-4 mm-sized papules that are usually located on the chest and extremities of children and young adults. Histologically, small cysts are observed in the mid-dermis and these cysts contain multiple hair shafts and keratinous materials. We report here on a case of eruptive vellus hair cysts that developed on a rare site, the labium major.

Intratarsal keratinous cysts of the Meibomian gland: distinctive clinicopathologic and immunohistochemical features in 6 cases

PURPOSE

To describe 6 patients representing a new entity of Meibomian gland keratinous cysts.

DESIGN

Retrospective, interventional, clinicopathologic study.

METHODS

Review of clinical histories and findings, histopathologic evaluations, and immunohistochemical studies of the cysts' linings with monoclonal antibodies directed against cytokeratins and cell surface epithelial markers.

RESULTS

Six patients with an average age of 62.5 years had noninflamed, upper eyelid nodules fixed to the tarsus. Eyelid eversion revealed a white-yellow nodular bulge in 3 cases, a bluish coloration in 2 cases, and a translucent appearance in 1 case. The cysts were lined by undulating squamous epithelium possessing an inner eosinophilic cuticle that produced a peculiar refractile, strand-like intracavitary keratin. Immunostaining for cytokeratin 17 and carcinoembryonic antigen showed strongly positive results in the Meibomian gland cysts and, by comparison, negative results in cutaneous epidermal cysts. Multiple recurrences occurred after incomplete excisions.

CONCLUSIONS

After chalazia and sebaceous cell tumors, Meibomian gland keratinous cysts seem to be the third most common primary intratarsal lesion. Anterior fixation to the tarsus and posterior protrusion beneath the palpebral conjunctiva without inflammation suggest the diagnosis. Histopathologic and immunohistochemical evaluations can distinguish unequivocally the current entity from common epidermal cysts. The optimal treatment consists of an en bloc excision of the cyst with a tarsectomy, or else wide excision with intratarsal cautery of any remnants of the cellular lining.

Dermal cysts: a dermatopathological perspective and histological reappraisal

Dermal cysts constitute an extremely common entity routinely encountered in dermatology and dermatopathology practice. Their ubiquity, overlapping clinical presentation, dermal location, and histologic diversity can engender diagnostic quandary. Though basically defined by the histologic presence of an epithelial lining, cysts derive from a variety of sources including developmental defects, trauma, and tumoral degeneration. Herein, we will discuss the dermatopathologic attributes of the more common dermal cyst entities, updating the most recent and pertinent literature.

Eruptive vellus hair cysts: an effective extraction technique for treatment and diagnosis

BACKGROUND

Eruptive vellus hair cysts are uncommon developmental anomalies of vellus hair follicles that are observed in young patients. Two patients were evaluated for asymptomatic flesh-coloured papules appearing on the chest, abdomen and axillae. Lesions of both patients were diagnosed histologically as eruptive vellus hair cyst, which is a disorder with no standard treatment option.

OBJECTIVE

To introduce an alternative treatment and diagnostic technique for eruptive vellus hair cysts and to evaluate this technique's effectiveness histopathologically.

MATERIALS AND METHODS

We treated the lesions by using cautery and a standard dissecting forceps under topical anaesthesia. After puncturing the overlying skin in the centre using the sharp-tipped cautery point, we grasped the base of the cyst using a standard dissecting forceps and we extracted the cysts out. In patient 1, extracted cysts were sent for histopathological examination; in patient 2, microscopic examination of the extracted material was performed in potassium hydroxide preparations.

RESULTS

Over 150 cysts were extracted with this technique in two patients. The technique was simple, quick and tolerated well. No lesion recurrence was observed after 4 months. On histopathological examination, extracted cysts were observed to have cyst walls. In patient 2, the diagnosis was made within minutes by microscopic examination of the potassium hydroxide preparations of the extracted material.

CONCLUSION

Our extraction technique is a simple and effective treatment option for these cysts. It can be regarded as curative since the cyst walls were also extracted. Microscopic examination of the potassium hydroxide preparation of the extracted cysts suggests that this technique can also be used as a simple diagnostic procedure.

Early recurrence of eruptive vellus hair cysts after Er:YAG laser therapy: case report and review of the literature

BACKGROUND

Therapy of eruptive vellus hair cysts (EVHCs) often leads to unsatisfying results or recurrences. Recently, erbium:yttrium-aluminum-garnet (Er:YAG) laser therapy has been recommended in this condition.

OBJECTIVE

To report the results of Er:YAG laser treatment and discuss the treatment options in EVHC, presenting a review of the literature.

METHODS

Full-face Er:YAG laser therapy was performed in a 30-year-old female patient with a 15-year history of cosmetically bothersome facial EVHCs.

RESULTS

Immediately after the laser treatment, the ablated skin showed an even surface, presenting no residual signs of EVHCs. After reepithelialization, however, early recurrence of EVHCs occurred. Recurrence was also observed in the previously treated test spot, where slight atrophy indicated deeper ablation.

CONCLUSION

Er:YAG laser therapy might be a treatment option for distinct lesions of EVHCs but proved to be ineffective in a case of EVHCs in the face, where the depth of ablation is limited owing to the risk of atrophy or scarring and where deep enucleation of distinct single cysts was not possible owing to the dense dissemination of the lesions. Despite numerous treatment options reported in the literature, therapy for EVHCs is still challenging owing to recurrences or side effects.

Basal cell carcinoma with sebaceous differentiation

Some authors have used sebaceous epithelioma as a synonym for basal cell carcinoma (BCC) with sebaceous differentiation. However, our review of the literature revealed that definite cases of BCC with sebaceous differentiation that provide adequate clinical and histopathologic information are scarce. We present the case of a 72-year-old woman with a pigmented nodular lesion on her right ala nasi region, clinically diagnosed as pigmented BCC. Histopathologically, this nodular lesion, which was completely excised, showed typical features of BCC. It was noteworthy that within one aggregation of the presented BCC, tiny and small duct-like structures lined by cornified layers with a crenulated inner surface were seen. Vacuolated cells were scattered within a few aggregations, and they had foamy, bubbly cytoplasm and starry nuclei. The vacuolated cells were immunohistochemically positive for epithelial membrane antigen (EMA). These histopathologic findings demonstrated unquestionable sebaceous differentiation in this BCC, namely BCC with sebaceous differentiation, which should be distinguishable from both sebaceoma and sebaceous carcinoma. The small duct-like structures lined by eosinophilic cuticle, indicating apocrine differentiation, were also observed in this BCC.

Eruptive vellus hair cysts in a patient with Lowe syndrome

We present a 20-year-old patient with Lowe syndrome and eruptive vellus hair cysts. Also known as oculocerebrorenal syndrome, it is an X-linked recessive disorder localized to Xq24-26.1. The phenotypic features of this disorder are Fanconi-type renal failure, mental retardation, and various eye abnormalities. The causative gene, oculocerebrorenal-Lowe 1 (OCRL1), encodes a phosphatase whose function is to regulate the phosphatidylinositol pool of intracellular signaling molecules that regulate the release of lysosomal enzymes in tissues. Low levels of this phosphatase lead to the extracellular release of lysosomal enzymes in organs such as the eye, brain, and kidney, with the resulting tissue damage most likely accounting for the characteristic phenotype. Our patient with Lowe syndrome had several discrete, dome-shaped papules on his midchest. They clinically resembled either eruptive vellus hair cysts or steatocystoma multiplex. Histologically they were most diagnostic of eruptive vellus hair cysts, which are not a known feature of Lowe syndrome. We present a hypothesis based on the known biochemical deficiencies resulting from the mutations in the OCRL1 gene, which may account for the cyst formation. To our knowledge, this is the first reported case of skin findings associated with this disorder.

A simple surgical technique for the treatment of steatocystoma multiplex

BACKGROUND

Since steatocystoma multiplex is an uncommon disorder, its treatment has not been discussed in detail in the textbooks and surgical excision is the most commonly mentioned method. In this article, we describe a very simple surgical technique, which was developed by modifying previous reports.

METHODS

A 29-year-old woman, diagnosed clinically and histologically as steatocystoma multiplex, was treated with this modified technique. We punctured the cysts under local anesthesia with a sharp-tipped cautery point and evacuated the contents by squeezing the cyst with a fine forceps. Then, the cyst wall was grasped by the forceps and the sacs were extracted through small holes. More than 50 cysts were treated.

RESULTS

The treatment was well tolerated by the patient. No complications developed during or after the procedure. After 14 months follow up no recurrences were observed and the results were cosmetically excellent.

CONCLUSIONS

This modified technique is very simple and time saving. Its cosmetic and long-term results are successful. We believe that it must be considered as the treatment of choice for steatocystoma multiplex.

Persistent milia, steatocystoma multiplex and eruptive vellus hair cysts: variable expression of multiple pilosebaceous cysts within an affected family

BACKGROUND

Steatocystoma multiplex (SM) and eruptive vellus hair cysts (EVHC) are conditions characterized by numerous cutaneous cysts with a clinical resemblance, such as age of onset, location, appearance of the lesions and mode of inheritance, but with distinctive histologic features. Recently, some authors have proposed that the two conditions are variants of one entity originating in the pilosebaceous duct, while others suggest that SM and EVHC are two distinct entities, on the basis of the different expression of keratins. Milia are small round cysts, commonly involving the face. In 1994, Menni and Piccinno reported the first association, in a family, between persistent infantile milia in a 9-month-old girl and SM in the father. The authors hypothesized a relationship between these two conditions.

OBJECTIVE

We describe a family in which the mother showed cystic lesions and milia and her 4-year-old son and her 18-month-old daughter presented persistent infantile milia.

METHODS

In addition to the clinical and genetic documentation, a biopsy was performed in the son and two biopsies in the mother.

RESULTS

The histologic examination of one of the son's milium-like papules showed in the superficial dermis a small cyst typical of a milium. In serial sections it was possible to see a connection with a vellus hair follicle by an epithelial pedicle. The histologic examination of one of the mother's papules on the forehead showed a large round cystic structure with histologic features of EVHC. Close to the cyst wall, serial sections showed flattened sebaceous gland lobules. The histologic findings of the second biopsy taken from the chest showed the typical features of a steatocystoma.

CONCLUSIONS

The relationship between milia, SM and EVHC is discussed; the three disease should be considered as subtypes of multiple pilosebaceous cysts that may all present overlapping histologic features. The different level of the pilosebaceous duct where the cyst originates should explain the different clinical manifestations.

Eruptive vellus hair cyst and epidermoid cyst in a patient with pachyonychia congenita

We report the first case of pachyonychia congenita (PC) associated with both eruptive vellus hair cyst (EVHC) and epidermoid cyst. The patient is a 12-year-old Japanese girl who presented with two natal teeth at birth. She had thickening and discoloration of the fingernails and toenails, plantar hyperkeratosis, palmar-plantar hyperhidrosis and multiple cutaneous cysts. Histologic examination revealed EVHC and epidermoid cyst.

Retiform/racemiform neoplasm with features of clear cell hidradenoma

We report a case of a 78-year-old woman with a tumor of the left cheek. The tumor was a well-circumscribed cystic/solid nodule with a racemiform and reticulated pattern of growth of its epithelial cells, and mucinous and fibrocytic stroma. The epithelial cords and strands were continuous with the apocrine lining of large cystic structures. The main bulk of the epithelial component was formed by the proliferation of clear cells. This tumor is an example of an unusual benign neoplasm with racemiform and retiform patterns having a histogenetical link with the folliculo-sebaceous-apocrine unit.

Immunohistochemical analysis of cytokeratin expression in multiple eccrine hidrocystoma

The histologic diagnosis as eccrine hidrocystoma may contain some other cysts which do not originate from the eccrine sweat glands. Some authors have suggested that true eccrine hidrocystoma does not exist. However, multiple eccrine hidrocystoma (Robinson type) is a distinct clinical entity which is characterized by multiple translucent papules around the eyelids which appear in warm weather. Cytokeratin expression in 8 cases of multiple type of unequivocal eccrine hidrocystoma was analyzed immunohistochemically. Immunoreactivities in our cases were similar to those of eccrine dermal ducts. Therefore, we confirmed that these tumors were derived from the eccrine dermal duct, not from the other appendages, and that true eccrine hidrocystoma exists.