Version 2: Rhizopus homothallicus, an uncommon causative agent of Rhino-orbital mucormycosis: A Case report

Introduction: Rhizopus oryzae is the most common Mucorales to cause angio-invasive infections though other species may also be found to be associated with different type of invasive infections. This case is about an uncommon species of Mucorales found to cause fungal sinusitis.

Case presentation: A male patient in his late 60s with known history of uncontrolled type 2 diabetes for about last 10 years presented with headache, nasal congestion and with history of fever in recent past. As condition did not improve with initial symptomatic treatment given, further workup was advised. Magnetic resonance imaging (MRI) was carried out which was suggestive of sinusitis. Biopsy was taken from affected sinus for further testing and work up. Microscopic examination from material taken out by biopsy showed few broad aseptate hyaline hyphae with right angle branching (Figure 1).  Fungal culture in Sabouraud Dextrose Agar media incubated at 37^o C and 25^o C showed white cottony growth within 3 days. Lactophenol Cotton Blue mount showed broad, aseptate hyphae with not-well-developed sporangiophores bearing few globose sporangia and many large numbers of golden brown zygospores with stellate walls and with suspensor cells, which was identified as Rhizopus homothallicus. Liposomal amphotericin B was given for treatment along with resection of local infected area. Subsequently patient improved with treatmen

Conclusion: Our purpose of reporting this case was to highlight the fact that though uncommon this species may emerge sporadically. More cases like this may be reported in future from different parts of the world as well.