Oropharyngolaryngeal Sarcocystosis and Histoplasmosis Co-Infection in a Patient with Systemic Lupus Erythematosus

Sarcocystosis is an uncommon zoonotic coccidian protozoal infection caused by Sarcocystis spp. Muscular sarcocystosis have been detected in patients with various types of cancer but co-infection with histoplasmosis has never been reported. We report a 39-year-old woman with active lupus nephritis who presented with hoarseness for eleven months. Physical examination and magnetic resonance imaging revealed an irregular exophytic mass at the left oropharynx and the left true vocal cord. The histopathologic diagnosis was oropharyngolaryngeal sarcocystosis and histoplasmosis. She was treated with oral itraconazole for histoplasmosis. The authors briefly review the clinicopathologic features and pathogenesis of oropharyngolaryngeal sarcocystosis and histoplasmosis and conclude the possibility of co-infection of oropharyngolaryngeal sarcocystosis and histoplasmosis, especially in immunocompromised patient.


Case Report
Sarcocystosis is an uncommon protozoal parasitic infection of human being caused by Sarcocystis spp. However, the outbreaks of muscular sarcocystosis have been recently documented [1,2]. In addition, we published the interesting case of sarcocystosis concomitant with laryngeal squamous cell carcinoma in September 2011 edition of Southeast Asia journal of tropical medicine and public health [3]. Herein, we supplementary report a rare case of concomitant oropharyngolaryngeal sarcocystosis and histoplasmosis in a patient with systemic lupus erythematosus (SLE). A combined coccidian parasitic and fungal infection has never been reported.
A 39-year-old woman presented with hoarseness for eleven months. Her underlying disease was systemic lupus erythematosus, diagnosed 8 years earlier with criteria of lupus nephritis (class III), arthritis, oral ulcer, and positive anti-nuclear antibody. She was treated with intravenous high-dose of cyclophosphamide and corticosteroids. A physical examination showed an irregular mucosal surface at the left true vocal cord. The left oropharynx showed an irregular ulcer. Magnetic resonance imaging exhibited a swelling lesion at the glottic region, left aryepiglottic fold, left lateral oropharyngeal wall, and left oral mucosa (Figure 1). The endoscopic biopsy was performed. Serological testing for IgG/IgM anti-Toxoplasma antibody was negative.
The histopathology revealed an acanthotic squamous mucosa with diffuse infiltration of a poorly-formed granuloma. There were multiple intracellular yeasts in macrophages ( She had been treated with oral itraconazole for histoplasmosis. Later on, she was referred to our hospital due to progressive jaundice after seven weeks of therapy. Her liver function test shows elevated liver enzymes as shown in Table 1. Itraconazole-induced cholestasis was diagnosed. She developed renal failure that required dialysis. Multiple hyperpigmented papules at her right leg showed palisading granulomatous dermatitis.
She was treated as disseminated histoplasmosis. Antifungal therapy was switched to liposomal amphotericin B. She subsequently developed hepatic failure, hepatic encephalopathy, status epilepticus, and septicemia. Finally, she developed multiorgan failure and succumbed to the complication of disease, three months after the diagnosis of oropharyngolaryngeal sarcocystosis and histoplasmosis. No autopsy was performed.
A variety of parasitic protozoan have been identified in the muscular tissue, but only Toxoplasma spp, Neospora spp, and Sarcocystis spp. have been identified as pathogenic for humans.
The histopathology shows sarcocyst measuring between 40 µm to 456 µm in length and 26 µm to 142 µm in width [3]. The cystic wall is composed of hyaline eosinophilic monomorphous material and is well demarcated from the surrounding muscular fibers. The bradizoites appears as crescentric "banana" shaped structures. The clinical and histopathological features of muscular sarcocystosis and intestinal sarcocystosis in humans are summarized in Table 2.  However, additional diagnostic studies such as immunohistochemical stain for Toxoplasma gondii should be performed. Therefore, the histopathologic examination is of value for identifying unsuspected conditions and may reveal major unexpected findings that are of clinical importance and necessary for the diagnosis, treatment and prevention of the infectious disease, especially in immunocompromised host. Oropharyngolaryngeal histoplasmosis should be differentiated between primary histoplasmosis and progressive disseminated histoplasmosis. Among immunosuppressed patient who is prone for development of dissemination should have thought evaluation for multiorgan involvement. Oropharyngolaryngeal histoplasmosis treated like subacute progressive disseminated histoplasmosis.
For moderately severe to severe progressive disseminated disease, liposomal amphotericin B is recommended for 1-2 weeks or longer depends on the severity of disease, followed by oral itraconazole for a total at least 1 year. The overall prognosis is good. However, our patient had the delayed diagnosis and treatment, which lead to progression of disease to presumptive disseminated histoplasmosis.
She also had the itraconazole-induced cholestasis and subsequently developed hepatic failure, hepatic encephalopathy, status epilepticus, and septicemia, which were the major complication and cause of death.
Muscular sarcocystosis has no specific treatment [1]. The overall prognosis is excellent. Proper disposal of human feces and careful animal husbandry are mandatory in the control of muscular sarcocystosis. An accurate diagnosis requires recognition of the clinicopathological finding and a high index of suspicion. Public health education on transmission, combined with proper diagnosis and treatment are crucial [3].  We would like to emphasize that oropharyngolaryngeal sarcocystosis may accompany with an infectious disease such as histoplasmosis, especially in the immunocompromised patient. The authors also would like to alert clinicians and pathologists to suspect the possibility of such concomitance and the necessity of early diagnosis.