TY - JOUR
T1 - Borderline Tuberculoid Leprosy Masquerading as Granuloma Annulare
T2 - A Clinical and Histological Pitfall
AU - Zhu, Tian Hao
AU - Kamangar, Faranak
AU - Silverstein, Marc
AU - Fung, Maxwell A
PY - 2017/4/1
Y1 - 2017/4/1
N2 - Introduction: Leprosy is a chronic granulomatous disease caused by Mycobacterium leprae, an intracellular acid-fast bacillus that tends to infect the skin and peripheral nerves. Because of the wide array of cutaneous manifestation, diagnosis is not always straightforward, especially in nonendemic regions of the world such as the United States. Case Report: The authors report an unusual case of borderline tuberculoid leprosy in an 80-year-old white woman from California. Clinical examination revealed multiple nonscaly annular plaques, with central clearing and absence of lesional anesthesia, distributed over the trunk and extremities initially clinically diagnosed as granuloma annulare (GA). After 2 years of unsuccessful treatment with topical corticosteroid, biopsy revealed a palisaded and interstitial granulomatous infiltrate with necrobiosis, without discrete granulomas, compatible with GA. However, the presence of perineural lymphocytes in the reticular dermis prompted a Fite stain, which revealed acid-fast bacilli within the Schwann cells of a small peripheral nerve, pathognomonic for leprosy. Conclusion: This is the first reported case of leprosy masquerading both clinically and histologically as GA. Dermatopathologists should be aware of the possibility of leprosy given the presence of perineural lymphocytes amidst any pattern of granulomatous infiltrate and obtain a Fite stain. ©
AB - Introduction: Leprosy is a chronic granulomatous disease caused by Mycobacterium leprae, an intracellular acid-fast bacillus that tends to infect the skin and peripheral nerves. Because of the wide array of cutaneous manifestation, diagnosis is not always straightforward, especially in nonendemic regions of the world such as the United States. Case Report: The authors report an unusual case of borderline tuberculoid leprosy in an 80-year-old white woman from California. Clinical examination revealed multiple nonscaly annular plaques, with central clearing and absence of lesional anesthesia, distributed over the trunk and extremities initially clinically diagnosed as granuloma annulare (GA). After 2 years of unsuccessful treatment with topical corticosteroid, biopsy revealed a palisaded and interstitial granulomatous infiltrate with necrobiosis, without discrete granulomas, compatible with GA. However, the presence of perineural lymphocytes in the reticular dermis prompted a Fite stain, which revealed acid-fast bacilli within the Schwann cells of a small peripheral nerve, pathognomonic for leprosy. Conclusion: This is the first reported case of leprosy masquerading both clinically and histologically as GA. Dermatopathologists should be aware of the possibility of leprosy given the presence of perineural lymphocytes amidst any pattern of granulomatous infiltrate and obtain a Fite stain. ©
KW - Fite stain
KW - granuloma annulare
KW - granulomatous
KW - leprosy
KW - perineural lymphocytes
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U2 - 10.1097/DAD.0000000000000698
DO - 10.1097/DAD.0000000000000698
M3 - Article
C2 - 28328616
AN - SCOPUS:85015907102
VL - 39
SP - 296
EP - 299
JO - American Journal of Dermatopathology
JF - American Journal of Dermatopathology
SN - 0193-1091
IS - 4
ER -