Dear Editor, Medicopsis romeroi is a rare example of subcutaneous phaeohyphomycosis caused by traumatic implantation of fungal organisms. According to the National Center for Biotechnology Information, M. romeroi belongs to the Ascomycota phylum. This fungus produces brown-colored, septate hyphae without conidia. M. romeroi, previously recognized as Pyrenochaeta romeroi, is primarily found in the soil and plants of subtropical and tropical regions and has the potential to infect humans through direct inoculation.1M. romeroi is a rare infection, and the cytomorphological features of the fungus are not well-established. We aim to elucidate the cytomorphological characteristics of Medicopsis. A 40-year-old female presented at the fine needle aspiration (FNA) outpatient department with a swelling on the right dorsal aspect of her wrist. She had been experiencing the swelling for the past 6 months, accompanied by pain. The initial clinical diagnosis indicated a ganglion cyst. The patient had a preexisting condition of rheumatoid arthritis and was undergoing native medicinal treatment. She did not have a history of diabetes, and human immunodeficiency virus serology results were negative. Additionally, there was no reported history of fever. On ultrasonography, a well-defined, heterogeneously hypoechoic lesion measuring 3 cm × 2.7 cm × 2.6 cm was observed on the dorsal aspect of the distal forearm, closely abutting the ulnar bone. No internal vascularity was detected, and there was no extension into the wrist joint. While the possibility of a ganglion cyst was considered, an infective etiology could not be ruled out. The FNA cytology of the swelling yielded pus. Microscopic examination using May–Grünwald Giemsa (MGG) and Papanicolaou (PAP) stains revealed thin, septate branching hyphae appearing as negative images in MGG-stained smears within a necrotic background Figure 1A and B. The fungi were particularly challenging to detect on PAP-stained smears and exhibited a green coloration merging with the background Figure 1C and D. The stain for acid-fast bacilli was negative. Upon informing the clinician, a re-aspiration was performed, and the sample was sent for culture. Additionally, Periodic acid schiff and Gomori methenamine silver stain staining were conducted, which highlighted the acute branching septate hyphae of the fungus Figure 2A and B. The potassium hydroxide examination also showed a septate fungus, and black phaeoid molds were observed on culture Figure 2C; however, on lactophenol cotton blue preparation, no conidia were identified. A fungal culture grown on Sabouraud Dextrose Agar was further subjected to DNA extraction using a commercially available DNA extraction kit (HiYield Genomic DNA Kit, RBC, Taiwan). The extracted DNA underwent polymerase chain reaction (PCR) amplification using primers: internal transcribed spacer ITS1 (5′-TCCGTAGGTGAACCTGCGG-3′) and ITS4 (3′-TCCTCCGCTTATTGATATGC-5′). The amplified PCR product was subsequently sequenced; sequencing was performed commercially. The obtained sequence was then analyzed using GenBank BLAST alignment software. We found that the sequence showed 99% similarity with M. romeroi, and the sequence was submitted to the GenBank database and assigned the accession number PP600296. The patient was given a course of antifungals, and a 1-year follow-up did not show any relapse.Figure 1: (a) May–Grünwald Giemsa (MGG)-stained smears showing branched septate fungal hyphae appearing as negative images in a background of necrosis (400×; red arrow). (b) MGG-stained smears showing prominent vesicular swellings between the septations of hyphae (400×; green arrow). (c and d) Papanicolaou-stained smears showing hyphae merging with the background and staining green (400×; white arrows)Figure 2: (a) PAS Periodic acid schiff-stained smears highlighting fungal hyphae (200×). (b) Gomori methenamine silver stain-stained smears highlighting the acute branching of the fungus (200×). (c) Fungal culture tube showing black phaeoid growthPhaeohyphomycosis is a type of subcutaneous fungal infection that includes various infections such as zygomycosis, chromoblastomycosis, sporotrichosis, mycetoma, and rhinosporidiosis.2 It encompasses a group of infections caused by dematiaceous or pigmented filamentous fungi. These fungi have melanin in their cell walls and can manifest in various clinical presentations, ranging from cysts, plaques, ulcers, verrucous growths, and individual nodules on the skin to deep subcutaneous abscesses.3 Our case presented as a subcutaneous swelling without any overlying ulcer or maceration. M. romeroi is a rare cause of phaeohyphomycosis. However, the incidence has been rising. Clinically, it has nonspecific features. However, it has been mostly reported in immunocompromised individuals. It has also been described in a patient with rheumatoid arthritis on Disease modifying antirheumatic drugs, prednisolone, and methotrexate.4 Our patient also had rheumatoid arthritis and was on native medicines. The native medicine had some immunosuppressive properties. M. romeroi is a saprophyte commonly found in soil, plants, and decaying organic matter. Consequently, agricultural workers are at increased risk of infection. In the present case, although the patient was a housewife, she frequently tended to plants and maintained a home garden, which likely served as the source of exposure. The infection is typically acquired through direct inoculation following trauma with a plant thorn, splinter, or contaminated object and is most often reported in tropical and subtropical regions.4 In cytology, the fungal hyphae observed in phaeohyphomycosis are moniliform, measuring 2–6 μm in width, and exhibit considerable variation in length. Although brown pigment may be present, its observation is challenging due to its tendency to be masked by necrosis. Special stains such as Masson Fontana can be used to highlight the melanized hyphae.5 Acute angled to right-angled branching is a common feature.6 In our specific case, smears stained with MGG and PAP revealed a necrotic background. Upon careful examination, some unstained hyphae were identified in the MGG smears. Conversely, on the PAP-stained smears, appreciating the hyphae was extremely challenging. This contrasts with the typical fungal staining pattern, where PAP usually enhances fungal visibility more effectively than MGG. PAP stain usually shows fungal elements more clearly, likely because MGG has heavy background staining from necrosis that obscures morphological details.7 The hyphae generally displayed a moniliform appearance with the presence of acute, thin branching, reminiscent of Aspergillus. Additionally, vesicular swellings were frequently observed between the septations of the hyphae. In contrast to Aspergillus and other typical fungi, which get differentially stained in MGG and PAP-stained smears, these fungi were unstained in MGG and stained green in PAP, merging with the background.7 Zygomycetes are typically identified by their broad, non-septate or sparsely septate hyphae with nondichotomous branching. When fungal elements are scant, fragmented, or distorted by necrosis, accurate assessment of septation and branching becomes unreliable. In such settings, hyphae may appear swollen and atypical, leading to possible diagnostic errors. These pitfalls carry significant risk, as misinterpretation may result in inappropriate antifungal therapy or even unnecessary surgical intervention.8 The literature indicates that patients with Medicopsis spp. infections exhibit a favorable response to a combination of surgical drainage and debridement of the infected lesion, coupled with extended use of one of the triazoles, specifically itraconazole.9 Phaeohyphomycosis, a subcutaneous fungal infection, presents with diverse clinical manifestations, ranging from individual nodules to deep abscesses. In this specific case, a subcutaneous swelling initially misidentified as a ganglion cyst led to the identification of M. romeroi, a rare causative agent in a patient of rheumatoid arthritis. Cytological examination revealed distinct features of fungal hyphae, such as thin branching hyphae with the presence of prominent vesicular swellings in the hyphae. Unusual staining patterns, notably in PAP, further complicated hyphal recognition, deviating from typical fungal staining methods. Clinical and cytological findings underscore the importance of considering fungal infections, even rare ones, in the differential diagnosis of subcutaneous swellings. This is particularly crucial in patients with underlying conditions compromising their immune systems. The literature suggests a combined surgical and antifungal approach for managing Medicopsis spp. infections, reinforcing the significance of a comprehensive evaluation to ensure accurate diagnosis and timely implementation of appropriate therapeutic strategies. Acknowledgment None. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.
Philip et al. (2026) studied this question.