Pigmented follicular cyst

[Main Types of Cysts in Dermatopathology: Part 1]

Cystic structures represent one of the most common findings in dermatopathology. These encompass both cystic tumors and pseudocysts resulting from the accumulation of certain substances, such as mucin. In a two-part series (of which this is the first part), we have reviewed the principal types of cysts and pseudocysts that may be observed in cutaneous biopsies, examining their histopathological features and primary differential diagnoses. This first part encompasses infundibular cysts, eruptive dermoid cysts, pigmented follicular cysts, pilonidal cysts, tricholemmal cysts, milium cysts, hybrid cysts, bronchogenic cysts, as well as steatocystoma, hydrocystoma, and comedones.

Overexpression of hepatoma-derived growth factor in melanocytes does not lead to oncogenic transformation

BACKGROUND

HDGF is a growth factor which is overexpressed in a wide range of tumors. Importantly, expression levels were identified as a prognostic marker in some types of cancer such as melanoma.

METHODS

To investigate the presumed oncogenic/transforming capacity of HDGF, we generated transgenic mice overexpressing HDGF in melanocytes. These mice were bred with mice heterozygous for a defective copy of the Ink4a tumor suppressor gene and were exposed to UV light to increase the risk for tumor development both genetically and physiochemically. Mice were analyzed by immunohistochemistry and Western blotting. Furthermore, primary melanocytes were isolated from different strains created.

RESULTS

Transgenic animals overexpressed HDGF in hair follicle melanocytes. Interestingly, primary melanocytes isolated from transgenic animals were not able to differentiate in vitro whereas cells isolated from wild type and HDGF-deficient animals were. Although, HDGF-/-/Ink4a+/- mice displayed an increased number of epidermoid cysts after exposure to UV light, no melanomas or premelanocytic alterations could be detected in this mouse model.

CONCLUSIONS

The results therefore provide no evidence that HDGF has a transforming capacity in tumor development. Our results in combination with previous findings point to a possible role in cell differentiation and suggest that HDGF promotes tumor progression after secondary upregulation and may represent another protein fitting into the concept of non-oncogene addiction of tumor tissue.

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.

Multiple pigmented follicular cysts of the vulva successfully treated with CO2 laser: case report and literature review

BACKGROUND

A pigmented follicular cyst is an uncommon epithelial cyst, typically occurring as a single asymptomatic pigmented papule or nodule on the head and neck of adult men. To the authors' knowledge, no previous cases of vulvar pigmented follicular cyst have been reported. Although benign, pigmented follicular cyst can affect quality of life when multiple and symptomatic.

OBJECTIVE

The objective was to describe the clinicopathologic features of vulvar pigmented follicular cyst and to evaluate the efficacy of CO(2) laser therapy in this region.

METHODS

A 62-year-old woman with multiple pigmented follicular cysts affecting the labia majora bilaterally is described. Owing to frequent inflammation and tenderness, continuous-wave CO(2) laser was used to treat the skin lesions under local anesthesia.

RESULTS

All cystic nodules were successfully ablated with CO(2) laser. The patient tolerated the procedure well and had a satisfactory cosmetic outcome.

CONCLUSION

CO(2) laser is a tolerable and effective therapeutic modality for multiple and symptomatic pigmented follicular cysts of the vulva.

Pigmented terminal hair cysts within an intradermal melanocytic naevus

The combination of melanocytic naevi and cysts of adnexal or epithelial origin has been described previously. Herein we describe a case of intradermal melanocytic naevus containing pigmented terminal hair cysts, a rare variant of epithelial cysts. Our observation suggests that pigmented follicular cysts and combined cystic-melanocytic lesions may be attributed to follicular occlusion.

Pigmented epidermal cysts

There are few reports documenting the presence of melanin or melanocytes in epidermal cysts. One hundred and twenty five epidermal cysts from Indian patients were analyzed for the presence of melanin pigment and their sites were noted. A Masson's Fontana stain and immunohistochemistry for S-100 protein and HMB 45 was performed for localization of melanin and melanocytes within the epidermal cysts. Seventy-nine (63%) of the epidermal cysts showed presence of melanin pigment or melanocytes to a variable extent. Melanin was not present in epidermal cysts occurring along lines of fusion of skin folds during embryonogenesis (e.g., ventral midline, inner canthus, nose, upper lip and in the distal most parts like leg and foot and also scrotum). Ten of the 79 epidermal cysts showed extensive accumulation of melanin pigment and infiltration with melanophages in the cyst wall. Four of these patients gave history of trauma and the follow-up was uneventful in two of them. Pigmentation of epidermal cysts thus follows a definite anatomic pattern and is dependent on the natural skin color. Large amount of pigment accumulation within epidermal cysts occurs after cyst rupture and is not associated with hemochromatosis as was believed in the past.