case5

A CLINICAL AND HISTOPATHOLGICAL STUDY OF NEVUS SEBACEUS

Neerja Puri

Corresponding author:  Dr Neerja Puri    e-mail: neerjaashu@rediffmail.com

Abstract

Background Nevus sebaceus (NS), otherwise designated as 'organoid nevus', involves proliferative changes of the sebaceous glands, sweat glands, and the hair follicles. It displays a range of appearances, depending on the lesion's age. Aims To study the clinical features along with histopathological study of 20 cases of nevus sebaceus. Methods We selected 20 cases of nevus sebaceous for the study. Results Clinically,verrucous plaques were seen in 60% patients, papules were seen in 25% patients and patches were seen in 15% patients. All of them showed abortive/immature hair follicles characterized by cords of undifferentiated, basaloid cells resembling the embryonic stages of hair follicle. Conclusions To conclude, NS is an organoid nevus, i.e a hamartoma consisting of various elements indigenous to the organ and not merely the sebaceous units.

 

Key words:  Nevus sebaceous; histopathological; sebaceous glands; tumours

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Introduction

In 1895, Jadassohn first described nevus sebaceus (NS), a circumscribed hamartomatous lesion predominantly composed of sebaceous glands [1]. However, Pinkus designated this disease 'organoid nevus', as the changes are not confined only to the sebaceous glands but also involve proliferative changes of sweat glands and hair follicles [2]. The lesion is interesting because its morphologic appearances vary with the age of the lesion [3]. As a consequence, there is a great likelihood of missing the diagnosis if only the classical findings of a well-developed NS are looked for. It is also associated with a range of secondary tumors, both benign and malignant. They include benign adnexal tumors such as trichoblastoma, syringocystadenoma papilliferum, trichilemmoma, sebaceoma, nodular hidradenoma, hidrocystoma, and eccrine poroma [4].

 

Aims

1. To study the clinical features of 20 cases of nevus sebaceous. 

2. To the histopathological study of all the cases.

 

Material and Methods

We selected 20 cases of nevus sebaceous for the study. Written informed consent of all the patients was taken for the study. Prior permission of the hospital ethical committee was taken for the study. Routine investigations were done in all the patients. Specialized investigations in the form of cutaneous biopsy was performed in all the patients.

 

Results

The data was collected and the results were analyzed statistically.

 

Sr No	Clinical  Appearance	Number	Percentage
1	Verrucous plaques	12	60
2	Papules	5	25
3	Patches	3	15

Table I. Clinical appearance of lesions

 

Sr No	Histopathological Feature	Number	Percentage
1	Acanthosis	16	80
2	Papillomatosis	16	80
3	Hyperkeratosis	16	80
4	Apocrine gland dilatation	4	20
5	Eccrine gland hyperplasia	3	15
6	Dilated keratin filled infundibula	5	25
7	Immature hair follicles	20	100
8	Immature sebaceous glands	4	20

Table II. Histopathological features of nevus sebaceus

 

Discussion

The age group of the patients ranged from 8 years to 50 years of life. The mean age of the patients was 24 years. Males outnumbered females and male: female was 1.5: 1. Regarding the clinical appearance of lesions verrucous plaques were seen in 60% patients (Fig. 1), papules were seen in 25% patients and patches were seen in 15% patients. All of them showed abortive/immature hair follicles characterized by cords of undifferentiated, basaloid cells resembling the embryonic stages of hair follicle. Germ and papilla formation was seen. Twenty percent of cases showed immature sebaceous glands characterized by cells with larger nuclei, eosinophilic cytoplasm, and indistinct cell borders. The sebaceous glands also showed hyperplasia, crowding. Twenty percent of the cases showed dilated, prominent apocrine glands (Fig. 2) and fifteen percent showed prominent, dilated eccrine glands. Epidermal changes in the form of acanthosis, papillomatosis, and hyperkeratosis were seen in eighty percent cases. Dilated keratin-filled infundibula were seen in 25% of the cases. The most striking feature was the absence of normal terminal hair follicles within the confines of the lesion, sharply demarcated from the adjacent skin which was seen in all the cases [5,6]. Nevus sebaceus is usually present at birth; and in its most common location, viz., the scalp, it is manifested by a well-defined area of alopecia with smooth surface and yellow-to-orange discoloration. In the infantile stage, the epidermis is only slightly acanthotic and may be hyperpigmented. The hair follicles are small, incompletely formed, and are often represented by solid cords of undifferentiated basaloid cells. The sebaceous glands are not prominent.

 

 

Figure 1. Nevus sebaceus in a 15 years old girl

Figure 2. Photomicrograph of nevus sebaceus showing hyperkeratosis,acanthosis, papillomatosis with dilated prominent apocrine gland s(H&E stain 100X)

 

Conclusion

To conclude, though malignancy is uncommon, a cautious histologic analysis is mandated, especially if there are clinical changes in a lesion.

 

What’s New

NS is an organoid nevus, i.e a hamartoma consisting of various elements indigenous to the organ and not merely the sebaceous units. Normal terminal hair follicles are characteristically absent in the lesion although the same may be seen in rest of the epidermis, a feature of diagnostic importance, not usually highlighted in literature.

 

REFERENCES

1. Lantis S, Leyden J, Heaton C: Nevus sebaceous of Jadassohn. Arch Dermatol. 1968;98:117-23.

2. Morioka S: The natural history of Nevus Sebaceous. J Cutan Pathol. 1985;12:200-13.

3. Alsaad KO: Skin adnexal neoplasms-Part I: An approach to tumors of pilosebaceous unit. J Clin Pathol. 2007;60:129-44.

4. Kaddu S: Malignant neoplasms associated with Nevus Sebaceous. Am J Dermatopathol. 1998;20:615-23.

5. Cribier B, Scrivener YG: Tumors arising in nevus sebaceous: A study of 596 cases. J Am Acad Dermatol. 2000;42:263-8.

6. Maheshwari V, Alam K, Prasad S, Sharma R, Khan AH, Sood P: Cerebriform nevus sebaceus: A rare entity. Dermatol Online J. 2006;12:21.