Perianal Histoplasmosis Presenting as a Mass Suspicious for Malignancy: A Case Report with Review of Gastrointestinal Manifestations of Histoplasmosis

Abstract

Patient: Male, 66Final Diagnosis: Perianal histoplasmosisSymptoms: Perianal painMedication: —Clinical Procedure: Surgical biopsy of the lesionSpecialty: PathologyObjective:Unusual clinical courseBackground:Disseminated histoplasmosis, a disease that can present years after exposure to the causative organism, may manifest in many diverse ways. Although the gastrointestinal tract is involved in most cases, the initial presentation occurring along the gastrointestinal tract, including the colon and rectum, is infrequent.Case Report:This case report describes a 66-year-old male patient who presented with an indurated painful perianal lesion that appeared highly suspicious for malignancy on imaging. The patient had no known history of well-established immunocompromised state except for a short course of prednisolone for chronic obstructive pulmonary disease management. A biopsy of the mass was performed, showing chronic inflammation with clusters of epithelioid histiocytes containing characteristic, PAS-fungus stain-positive, intracellular yeast forms consistent with histoplasmosis. There was no evidence of malignancy. A subsequent work-up revealed perihilar nodularity on chest X-ray suggestive of calcified granuloma, a positive Histoplasma Capsulatum Antigen test result, and mildly decreased CD4: CD8 ratio of unknown significance. HIV testing was negative. Treatment with itraconazole and terbinafine was initiated, and at 5-months follow-up, the patient reported significant improvement in signs and symptoms, with undetectable Histoplasma antigen on repeat testing.Conclusions:This case represents an extremely rare presentation of histoplasmosis infection, and highlights the fact that presenting symptoms of histoplasmosis can be vague and may mimic other disease processes, including neoplasia. Biopsy of the lesion with PAS staining and serologic testing is critical in establishing the correct diagnosis.

Gastrointestinal Histoplasmosis: A Descriptive Review, 2001–2021

“…Analysis of the 123 well-documented cases showed the clinical presentation of GIH was often non-specific and mimicked several other gastrointestinal conditions and pathologies, including abdominal tuberculosis (n = 3, 2.4%) [ 85 , 96 , 102 ], GIH and TB coinfection was reported in four [3.3%] cases [ 78 , 87 , 96 , 98 ], inflammatory bowel disease (n = 9, 7.3%) [ 21 , 33 , 40 , 52 , 69 , 75 , 89 , 105 , 107 ], intestinal obstruction (n = 15, 12.2%) [ 15 , 21 , 39 , 50 , 57 , 64 , 71 , 77 , 81 , 89 , 95 , 102 , 103 , 104 , 117 ], abdominal malignancy (n = 9, 7.3%) [ 14 , 16 , 31 , 80 , 83 , 101 , 102 , 108 , 112 ], GI bleeding (n = 29, 23.6%) [ 17 , 18 , 25 , 26 , 27 , 29 , 30 , 31 , 33 , 37 , 41 , 44 , 53 , 56 ,…”

“…Focusing on cases without HIV infection, the findings from our review suggest the need to also evaluate patients without HIV infection with risk factors for GIH including post-transplant patients on immunosuppressants [ 16 , 39 , 46 , 49 , 61 , 62 , 63 , 72 , 84 , 101 , 113 ], patients on immunosuppressants for other disease conditions [ 14 , 15 , 17 , 20 , 25 , 28 , 30 , 69 , 76 , 92 , 103 , 105 ] and patients with immunodeficiency syndrome [ 95 ] presenting with GI symptoms. This should be done regardless of the immune status of an individual as complications associated with GIH, such as acute abdomen [ 70 ], can also develop in immunocompetent patients.…”

Fungal perianal abscess as the initial presentation of disseminated coccidioidomycosis

“…The differential diagnosis of unresolved perianal abscesses should include actinomycosis and Crohn's disease when fistulas and draining sinuses are present [11] , [12] . Furthermore, patients coming from specific geographical regions should raise the possibility of tuberculosis [13] , endemic mycoses [14] , and parasites [15] (E.g., Enterobius vermicularis ); especially in immunocompromised hosts. In patients with high-risk sexual behavior sexually transmitted infections should be considered (E.g., HIV and Gonorrhea) [12] , [16] .…”

Progressive Disseminated Histoplasmosis Mimicking as Anal Carcinoma – Look at the Mountain, Not at Stone: A Case Report

“…In another case report, similar to our case, Matthew Wheel wright reported a 66-year-old male patient who presented with an anal ulcer with suspicion of the carcinoma on imaging. 10 Core biopsy of anal mass showed intracellular yeast suggestive of Histoplasma.…”