Histoid leprosy: case report.

Histoid leprosy is a rare but well-defined entity with specific clinical, histopathologic, and bacteriologic features. We present a case of histoid leprosy in an 84-year-old Egyptian male in view of the rarity of this condition. The patient presented with erythematous itchy discrete and coalescent papules that were distributed bilaterally and symmetrically on the front and back of the trunk. Before approaching us, he was initially misdiagnosed as a case of pityriasis rosea. There was no mucosal or facial affection and the patient's general examination was normal. Routine hematologic investigations, urine analysis, liver and renal function tests were all normal. Slit skin smear revealed acid-fast bacilli of BI - 6+ and MI - 50-60%. Histopathologic examination of hematoxylin and eosin-stained section revealed atrophic epidermis with flattened rete ridges and dermal infiltration by nodular granulomata formed of spindle shaped histiocytes with pyknotic nuclei oriented in a storiform pattern. Fite's stain for lepra bacilli showed plenty of acid fast bacilli. So, the diagnosis of histoid leprosy was made. Therefore, ROM therapy (rifampicin 600 mg, ofloxacin 400 mg, minocycline 200 mg) was started and followed by multi-drug therapy for 2 years.