Pathophysiology and Clinicopathologic Variants of Seborrheic Keratosis

Pathophysiology

Epidermal Growth Factor (EGF) or its receptor, has been shown to be involved in the formation of seborrheic keratosis. No significant differences of immunoreactive growth hormone receptor expression in epidermal keratinocytes in normal and seborrheic keratosis.

A high frequency of mutations in the gene encoding role in the tyrosine kinase receptor FGFR3 (fibroblast growth factor receptor 3) have been found in several types of seborrheic keratosis. This is the reason that the factor gene into the base in the pathogenesis of seborrheic keratosis. FGFR3 contained in transmembrane receptor tyrosine kinases that participate in signal transduction gives to the regulation of growth, differentiation, migration and cell healing. FGFR3 mutation present in 40% of seborrheic keratoses hyperkeratosis, 40% in seborrheic keratosis acanthosis, and 85% in seborrheic keratosis adenoids.

Seborrheic keratosis has many degrees of pigmentation. In pigmented seborrheic keratosis, proliferation of keratinocytes stimulate the activation of the melanocytes surrounding the melanocyte-stimulating secreting cytokines. Endothelin-1 has multiple simulation effect on DNA synthesis and melanization in human melanocytes and has been shown to be involved sabagai one important role in the formation of hyperpigmentation in seborrheic keratosis.

Clinicopathologic Variants

There are several different forms of histology and sometimes clinically for seborrheic keratosis:

1. Common Seborrheic Keratosis

Synonyms: basal cell papilloma, seborrheic keratosis solid.

This species is considered as classic lesions. Shaped like a mushroom, with a hyperplastic epidermis and demarcated who hang around the skin. The tumor is composed of basaloid cells were uniform. Sometimes, keratin cysts more, and may appear in the follicle and outside the follicle. Melanocytes sometimes appear in large quantities, and production of the pigment producing color black wound. Pigment transfer to keratinocytes seem quite normal.

2. Seborrheic Keratosis reticulated

Synonyms: adenoid seborrheic keratosis. Collection of basaloid cells down from the base of the epidermis. Keratin cysts surrounded by these cells. Smooth stromal eosinophilic collagen wraps around a collection of basaloid cells and can form a lesion that much.

3. Stucco keratosis

Synonyms: hyperkeratotic seborrheic keratoses, seborrheic keratoses digitate, seborrheic keratosis Serrated, seborrheic keratosis verrucous.

Stucco keratosis appears measuring 3-4 mm, color of skin color or white bumps that appear gray in the lower limbs. The appearance of epidermal cells as a church spire around the nucleus like a tangle of collagen forming hyperkeratosis basket. Keratinocytes that have vacuoles, whereas in verruca vulgaris lesions not found on this, even though clinical lesions may resemble a small wart virus.

4. Clonal Seborrheic keratosis.

This type of seborrheic keratosis-shaped nests of basaloid cells are not always circumscribed round and wrapped loosely in the epidermal tissue. Although most cells are keratinocytes, nests contains melanocytes in bulk. This keratinocytes size can vary.

5. Irritated Seborrheic Keratosis

Synonyms: inflamed seborrheic keratosis, cell basosquamous acanthoma. Skin disorders eksematous turned into a typical seborrheic keratoses. The cause of this is unknown eksematous reaction. It could be caused by trauma, but has not been proven. Histologically, a seborrheic keratosis showing parts of the inflammatory changes, many circle or vortex of eosinophilic squamous cells are evenly distributed and arranged like an onion. It resembles keratin pearls in scaly carcinoma cells, but can be distinguished by the large number of them, small size, and shape are limited. Keratinocytes in an irritated seborrheic keratosis showed high levels of keratinization or seborrheic keratoses grown compared with seborrheic keratosis common.

6. Seborrheic Keratosis with Squamous atypia

Atypical cells, and dyskeratosis can be seen in multiple seborrheic keratoses. The lesions can be very similar to Bowen's disease or invasive squamous cell carcinoma. It is not known causes of these changes, both as a consequence of irritation or activation, or sign squamous cell carcinoma. We recommend to remove these lesions entirely.

7. Melanoacanthoma.

Synonyms: pigmented seborrheic keratosis. Melanoacanthoma darker pigmented seborrheic keratosis from. Inside this lesion, there is a proliferation of dendritic melanocytes clear. Melanocytes are rich in melanin, otherwise very little around keratinocytes containing melanin. Melanocytes can develop into a nest, which extends from the basal layer to the superficial layer of the epidermis. These lesions are not potentially become malignant.

8. dermatosis Papulosa Nigra.

Dermatosis Papulosa nigra is a small papules on the face that looks at African Americans, but visible on darker skinned people of other races, it seems a variant of seborrheic keratosis. These lesions are papules eruption, which is pigmented, on the face and neck. They resemble tiny melanoacanthoma. Histological features such as seborrheic keratosis common but smaller.

9. The Sign of Leser-Trelat

Eruptive seborrheic keratoses multiple, also known as the sign of Leser-Trelat, mentioned internal malignancies associated with multiple hidden and is often accompanied by itching. The most commonly associated malignancy is adenocarcinoma of the stomach, colon, and breast. This sign has also been reported with a variety of tumors, including lymphomas, leukemia, and melanoma. This sign also mentioned that associated with hyperkeratosis of palms and soles associated with malignant disease and acanthosis nigricans with.

       Seborrheic keratosis phenomenon that can rupture, may indicate inflammation dermatosis centered around papilloma skin and seborrheic keratoses make it more visible phenomenon. Of course, the clinical skills required seborrheic keratosis lesions look elevation in patients with generalized dermatitis caused by many things. Chemotherapy, especially citarabine, can cause inflammation of seborrheic keratoses, especially when associated with signs of Leser-Trelat. Malignant acanthosis nigricans appear as much as 35% of patients with signs of Leser-Trelat, which showed similar mechanism. However, the exact relationship between eruptive seborrheic keratoses with multiple organ malignancy in remains to be explained.