Pyogenic granuloma and nodular Kaposi’s sarcoma: dermoscopic clues for the differential diagnosis

Pyogenic Granuloma-Like Kaposi's Sarcoma on the Ear in an Immunocompetent Patient

Botriomycome-like Kaposi disease is a rare clinical and pathological variant of Kaposi disease. Showing features of pyogenic granuloma (PG) and of Kaposi's sarcoma (KS), it was initially named KS-like PG and considered benign.[2] It is now considered a true KS and was renamed PG-like KS due to the clinical course and the presence of human herpes virus-8 DNA.[13],[14] This entity has been mostly described on the lower extremities, but other rare locations such as hand, nasal mucosa, and face have been reported in the literature.[1],[3],[4] The location on the ear in an immune-competent field, like in our patient, is a very rare finding, and very few cases have been reported in the literature.[5].

Dermoscopic rainbow pattern: A strong clue to malignancy or just a light show?

OBJECTIVE

Rainbow pattern is a dermoscopic finding composed of multiple colors simulating a rainbow. It is known as a characteristic feature of Kaposi's sarcoma. Here, we reported different non-Kaposi's sarcoma conditions with a rainbow pattern aiming to discuss the diagnostic significance of the finding.

METHODS

In this multicenter study, dermoscopic images of the non-Kaposi's sarcoma lesions having a histopathological diagnosis were reviewed for the presence of a rainbow pattern. Dermoscopic examination was performed by a polarized handheld dermoscope with x10 magnification.

RESULTS

A total of 840 lesions were reviewed and 21 (2%) non-Kaposi sarcoma lesions having dermoscopic rainbow pattern were detected. These lesions were as follows; pyogenic granuloma (n=4, 19%), hypertrophic scar (n=4, 19%), basal cell carcinoma (n=2, 10%), dermatofibroma (n=2, 10%), angiokeratoma (n=2, 10%), blue nevus (n=1, 5%), granuloma annulare (n=1, 5%), strawberry angioma (n=1, 5%), epidermal cyst (n=1, 5%), malignant melanoma (n=1, 5%), dissecting cellulitis (n=1, 5%) and subungual hematoma (n=1, 5%). The most common localization was limb (n=14, 67%) followed by face (n=3, 14%).

CONCLUSION

We suggest that the rainbow pattern is a complex and quite unspecific optic phenomenon which can be seen both in vascular and non-vascular lesions. Its diagnostic significance should be considered in the context of the other structural dermoscopic finding. To the best of our knowledge, to our knowledge, this is the most comprehensive study focusing on rainbow pattern in non-Kaposi's sarcoma lesions. Here, we also reported rainbow pattern in dissecting cellulitis, granuloma annulare and subungual hematoma which has not been shown to have rainbow pattern previously.