Dermatology: Practical and Conceptual Research Letter | Dermatol Pract Concept. 2025;15(2):5016 1 Fatal Disseminated Mucormycosis by Cunninghamella in Newly Diagnosed Acute Myeloid Leukemia: Case Report and Diagnostic Challenges Sebastián González-Valdés1, Magdalena Vial2, Renate Steffen1, Mauricio Lechuga3 1 Department of Dermatology, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile 2 Clínica San Francisco, San Fernando, Chile 3 Department of Dermatology, Complejo Asistencial Dr. Sótero del Río, Puente Alto, Chile Key words: Mucormycosis, Cunninghamella, Acute myeloid leukemia, Opportunistic infections, Fungal infections Citation: González-Valdés S, Vial M, Steffen R, Lechuga M. Fatal Disseminated Mucormycosis by Cunninghamella in Newly Diagnosed Acute Myeloid Leukemia: Case Report and Diagnostic Challenges. Dermatol Pract Concept. 2025;15(2):5016. DOI: https://doi.org/10.5826/dpc.1502a5016 Accepted: November 3, 2024; Published: April 2025 Copyright: ©2025 González-Valdés et al. This is an open-access article distributed under the terms of the Creative Commons Attribution- NonCommercial License (BY-NC-4.0), https://creativecommons.org/licenses/by-nc/4.0/, which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original authors and source are credited. Funding: None. Competing Interests: None. Authorship: All authors have contributed significantly to this publication. Corresponding Author: Mauricio Lechuga Ramírez, MD, Department of Dermatology, Complejo Asistencial Dr. Sótero del Río, Avenida Concha y Toro 3459, Puente Alto, Chile 8150215. E-mail: lechugamd@gmail.com Introduction Mucormycosis is a rare infection caused by fungi of the order Mucorales, with the most frequently associated genera being Rhizopus and Mucor, and to a lesser extent, Lichtheimia, Apophysomyces, Cunninghamella, and Rhizomucor [1-3]. The most significant risk factors for its development are di- abetes mellitus and hematologic malignancies [1,4,5], with acute myeloid leukemia (AML) posing the highest risk [3]. Depending on the affected body area, it is classified as rhino-orbital-cerebral, pulmonary, or cutaneous mucormy- cosis, followed less frequently by gastrointestinal, dissemi- nated, and uncommon presentations [1,4]. Case Presentation A 66-year-old man with chronic hypertension and prostate cancer in follow-up initially presented to the Emergency Department with a clinical picture of two weeks of fatigue and persistent epistaxis. Laboratory studies revealed a com- plete blood count showing hemoglobin of 10.5 g/dL, a white blood cell count of 19.600, platelets of 44.000, and 21% blasts, leading to hospitalization. A bone marrow examina- tion confirmed the diagnosis of AML, and an induction che- motherapy regimen of 7+3 (cytarabine and daunorubicin) was initiated. The patient developed respiratory distress, and a chest CT scan showed a consolidation in the right middle 2 Research Letter | Dermatol Pract Concept. 2025;15(2):5016 Figure 1. Clinical cutaneous and radiological pulmonary findings. (A) Chest CT scan with lung window showing evidence of consolidation in the right middle lobe and ipsilateral pleural effusion. (B-D) Hyperpigmented nodules with central necrotic crust and erythematous halo. lobe suggestive of invasive fungal infection with a right pleural effusion (Figure 1A), whose culture was positive for Cunninghamella spp. One week later, the patient developed hyperpigmented nodular skin lesions with erythematous ha- los and central necrosis (Figure 1B, 1C and 1D). Histopa- thology of the right lower limb lesion (Figure 2A-C) revealed suppurative interstitial dermatitis with aseptate, ribbon-like intravascular hyphae, intraluminal thrombosis, and culture also positive for Cunninghamella spp. An otolaryngology evaluation ruled out rhinosinusal involvement. Liposomal amphotericin B therapy was initiated, but the patient’s con- dition worsened, developing pleural empyema with signs of loculation. A video-assisted thoracotomy revealed a necrotic-appearing parietal pleural and pulmonary abscess, with microbiological studies confirming the previously de- scribed microorganism. The patient completed more than 30 days of liposomal amphotericin B, followed by a transition to oral isavuconazole. The patient died three months later due to secondary respiratory failure from a new pulmonary abscess. Conclusion We report a case of an uncommon presentation of mucormy- cosis in a disseminated form, which corresponds to the infec- tion of two or more non-contiguous organs or the isolation Research Letter | Dermatol Pract Concept. 2025;15(2):5016 3 Figure 2. Histopathological findings of cutaneous lesions. (A) H&E stain of a medium-sized vessel with intraluminal thrombosis. (B) H&E stain showing presence of intravascular aseptate hyphae and microthrombi. (C) Gomori-Grocott stain highlighting intravascular fungal elements (Courtesy of Dr. Claudio Pinto). of a Mucorales in the blood [1,2]. This form of presentation is associated with a high mortality rate, which, according to various series, ranges from 68% to 96%, especially in cases of infection by Cunninghamella spp [1,2,5]. Hematogenous dissemination more frequently occurs from the skin to other non-contiguous organs; however, the reverse occurs less than 3% of the time, hence the rarity of this case [2,3]. Cutaneous manifestations are diverse, primarily presenting as necrotic eschars, and less frequently as erythematous macules, black- ish nodules, target-shaped plaques, vesicles, blisters, and other forms [3,5]. Definitive diagnosis is made through his- topathological and microbiological studies. Early suspicion and multidisciplinary treatment are crucial in patients with risk factors and compatible clinical lesions, given the high morbidity and mortality associated with this condition [5,6]. References 1. Jeong W, Keighley C, Wolfe R, et al. The epidemiology and clin- ical manifestations of mucormycosis: a systematic review and 4 Research Letter | Dermatol Pract Concept. 2025;15(2):5016 meta-analysis of case reports. Clin Microbiol Infect. 2019; 25(1):26-34. DOI:10.1016/j.cmi.2018.07.011. PMID: 30036666. 2. Roden MM, Zaoutis TE, Buchanan WL, et al. Epidemiology and outcome of zygomycosis: a review of 929 reported cases. Clin Infect Dis. 2005;41(5):634-653. DOI:10.1086/432579. PMID: 16080086. 3. Petrikkos G, Skiada A, Lortholary O, Roilides E, Walsh TJ, Kontoyiannis DP. Epidemiology and clinical manifestations of mucormycosis. Clin Infect Dis. 2012;54 Suppl 1:S23-S34. DOI:10.1093/cid/cir866. PMID: 22247442. 4. Reid G, Lynch JP 3rd, Fishbein MC, Clark NM. Mucormycosis. Semin Respir Crit Care Med. 2020;41(1):99-114. doi:10.1055/s -0039-3401992. PMID: 32000287. 5. Skiada A, Rigopoulos D, Larios G, Petrikkos G, Katsambas A. Global epidemiology of cutaneous zygomycosis. Clin Dermatol. 2012;30(6):628-632. DOI:10.1016/j.clindermatol.2012.01.010. PMID: 23068150. 6. Cornely OA, Alastruey-Izquierdo A, Arenz D, et al. Global guide- line for the diagnosis and management of mucormycosis: an initiative of the European Confederation of Medical Mycology in cooperation with the Mycoses Study Group Education and Research Consortium. Lancet Infect Dis. 2019;19(12):e405-e421. DOI:10.1016/S1473-3099(19)30312-3. PMID: 31699664.