INTRODUCTION

Pigmented facial skin lesions may pose a significant diagnostic challenge, particularly when their clinical presentation is atypical. Seborrheic keratosis is the most common benign epidermal tumor in adults, characterized by a well-demarcated proliferation of keratinocytes [1,2]. Although typically easily recognizable, it may occasionally mimic malignant lesions, leading to diagnostic uncertainty.

Nasal involvement is uncommon and may present atypical clinical features, raising suspicion for malignancy, particularly melanoma or pigmented basal cell carcinoma [3]. Accurate diagnosis is essential due to the functional and aesthetic importance of this anatomical region.

We report a rare case of a giant seborrheic keratosis of the nasal ala clinically mimicking a malignant tumor, emphasizing the importance of histopathological examination in establishing the diagnosis.

CASE REPORT

A 28-year-old woman with no significant past medical history presented with a pigmented lesion on the right nasal ala, progressively increasing in size over a five-year period. Her general condition was preserved, with no associated systemic symptoms.

Clinical examination revealed a large exophytic, ovoid mass measuring approximately 6 cm in its greatest diameter. The lesion was verrucous, hyperkeratotic, and intensely pigmented, with a firm consistency. It was painless and did not bleed on contact (Fig. 1). The margins were well defined, with no evidence of infiltration of surrounding tissues. The lesion had a pedunculated base arising from the right nasal ala and caused partial obstruction of the ipsilateral nasal cavity. No signs of inflammation, ulceration, or suppuration were noted, and no cervical lymphadenopathy was detected.

Figure 1: Exophytic, hyperkeratotic, pigmented lesion of the right nasal ala partially obstructing the nasal cavity.

Based on these findings, the lesion was clinically suggestive of malignancy, particularly melanoma or pigmented basal cell carcinoma. A punch biopsy was performed. Histopathological examination revealed marked hyperkeratosis, acanthosis, and multiple horn cysts without cytological atypia, consistent with seborrheic keratosis.

The patient subsequently underwent complete surgical excision of the lesion, followed by reconstruction using a superiorly based nasolabial flap (Fig. 2). Histopathological analysis of the excised specimen confirmed the diagnosis.

Figure 2: Postoperative aspect at month 6 showing satisfactory aesthetic outcome after reconstruction of the right nasal ala.

Postoperative follow-up was uneventful, with a satisfactory functional and aesthetic outcome and no evidence of recurrence after 6 months.

DISCUSSION

Seborrheic keratosis is a common benign epidermal tumor, typically occurring in middle-aged and elderly individuals. It usually presents well-demarcated, pigmented lesions with a characteristic “stuck-on” appearance [4].

In the present case, several atypical features were observed, including young age, unusual nasal localization, large size, and marked pigmentation. These features expand the differential diagnosis to include melanoma, pigmented basal cell carcinoma, squamous cell carcinoma, Bowen’s disease, and melanocytic nevi.

The pathophysiology of seborrheic keratosis remains incompletely understood. Recent studies suggest a role for genetic alterations, particularly involving FGFR3 and PIK3CA mutations, as well as environmental factors such as ultraviolet exposure and skin aging [5].

Although seborrheic keratosis is benign, its association with malignant tumors has been reported. However, this relationship is generally considered to represent a coincidental coexistence (collision tumors) rather than true malignant transformation [6,7].

Histopathological examination remains the gold standard for diagnosis, especially in atypical presentations.

Various treatment options are available, including cryotherapy, curettage, electrocautery, laser therapy, and chemical peeling. However, in cases of diagnostic uncertainty or large lesions, complete surgical excision is preferred, as it allows both definitive diagnosis and treatment [8].

In our case, surgical excision combined with immediate reconstruction using a nasolabial flap provided satisfactory functional and aesthetic outcomes and allowed definitive histological confirmation.

CONCLUSION

Giant seborrheic keratosis of the nasal ala is a rare and atypical presentation that may clinically mimic malignancy. This case underscores the importance of histopathological examination in atypical lesions and highlights surgical excision as an effective diagnostic and therapeutic approach.

REFERENCES

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