A Case Report and Review of the Literature
* We describe a patient with extranodal non-Hodgkin lymphoma who developed systemic candidiasis after treatment with a cyclophosphamide-based chemotherapy regimen. Histologically, the fungal organisms demonstrated markedly enlarged blastoconidia with a variety of morphologic forms, mimicking other mycotic organisms, such as Cryptococcus neoformans, Blastomyces dermatitidis, and Paracoccidioides brasiliensis. The in vivo occurrence of such giant forms is rare, and when observed histologically may result in an erroneous diagnosis or a diagnosis of multiple mycotic organisms.
(Arch Pathol Lab Med. 2003;127:868-871)
Systemic candidiasis is increasingly a problem for immunocompromised patients Patients undergoing a prolonged course of cytotoxic drug treatment coupled with antibiotic treatment often develop an overgrowth of Candida species, especially Candida albicans, in the upper respiratory and gastrointestinal tracts. Cytotoxic chemotherapeutic agents used in the treatment of malignancies induce granulocytopenia, which predisposes to systemic spread of C albicans.
Giant forms of C albicans, usually referred to as "chlamydospores" in the literature, have been identified in vivo and in vitro,1-8 and their presence has been attributed to the pathogenicity of the organism,3 enabling it to survive in the adverse environment of body fluids. Furthermore, certain agents, such as cyclophosphamide, have been suggested as inducing agents of giant blastoconidia, both in vivo and in vitro.2 The presence of these giant forms in clinical specimens may present diagnostic confusion, as several morphologic features closely resemble those of giant Cryptococcus neoformans, Blastomyces dermatitidis, and Paracoccidioides. Given the poor prognosis of systemic candidiasis, early diagnosis and prompt treatment with antifungal agents is of utmost importance, and awareness of the potential presence of giant forms of C albicans may ultimately direct therapeutic intervention.
REPORT OF A CASE
A 69-year-old white man with a diagnosis of extranodal, nonHodgkin lymphoma presented with neutropenic fevers following his second cycle of a cyclophosphamide-based chemotherapy regimen. The diagnosis of lymphoma was based on a liver biopsy done several months earlier during an extensive workup of persistent nausea and diarrhea. Unable to tolerate food secondary to these complaints, the patient was on total parenteral nutrition for 6 months prior to his death. Medications included furosemide and spironolactone.
On admission, the patient was found to be neutropenic (white blood cell count, 0.6 x 10^sup 3^/(mu)L) and hypokalemic (3.0 mEq/L). Chest radiography on admission was unrevealing. The patient was pan-cultured and started on broad-spectrum antibiotics (vancomycin and cefepime) and granulocyte colony-stimulating factor. The patient was intubated on hospital day 4 for hypoxemia and respiratory distress. Postintubation chest radiography revealed bilateral, perihilar interstitial and alveolar opacities. He was transferred to the medical intensive care unit following intubation. Subsequent chest radiographs were consistent with bilateral bronchopneumonia with pleural effusions. Small nodular densities were noted at the right lung base. Antibiotic coverage was changed to trimethoprim-sulfamethoxazole (to cover suspected Pneumocystis carinii) and azithromycin. He did not receive any antifungal treatment. Blood cultures were negative for bacterial and fungal pathogens throughout the patient's hospital course. Smears and immunofluorescent stain of bronchoalveolar washings were negative for P carinii, but viral cultures grew parainfluenza virus and cytomegalovirus.
In the medical intensive care unit, the patient experienced episodes of hypotension requiring continual vasopressor medications. He was noted to be markedly edematous with low urine output and underwent continuous veno-venous hemofiltration for removal of excess fluid. On hospital day 7, the patient was noted to be acidotic (serum amylase, 1164 U; lipase, 1177 mIU/mL). A computed tomographic scan of the abdomen showed findings consistent with pancreatitis. The patient's clinical condition continued to deteriorate, and his white blood cell count continued to rise, reaching 40 000/mm. At the request of the patient's family, a do-not-resuscitate order was signed. The patient died on hospital day 20 without a confirmed clinical or microbiologic diagnosis. A full autopsy was performed.
At autopsy, gross inspection of the heart, lungs, kidneys, thyroid, liver, and pancreas revealed multiple, small (0.10.4 cm), white lesions that were suspicious for fungal abscesses. Cultures of tissue from the lung lesions grew C albicans. Histologic sections from the systemic autopsy showed Candida organisms invading arterial vessels of the pancreas, associated with thrombosis of the vessels and multiple necrotic infarcts of the pancreas. This invasion was also associated with extensive intraperitoneal fat necrosis. There was no evidence of residual lymphoma. Neuropathology was significant for a candidal meningo-encephalitis. Postmortem blood cultures grew only C albicans.
Abscesses composed of collections of polymorphonuclear neutrophils were found in many organs, including heart, lung, thyroid, liver, kidney, pancreas, and brain. In many instances, budding yeast forms and pseudohyphal forms typical of Candid species were apparent by light microscopy. In the pancreas, the hyphal forms were seen to invade arterial vessels, resulting in infarction of the pancreatic parenchyma. A large number of enlarged blastoconidia and enlarged pseudohyphae suggested the presence of a second mycotic agent (Figure, a and b).
Special stains, including Gram, Ziehl-Neelsen, mucicarmine, Gomori methenamine silver, and periodic acidSchiff, were performed to evaluate these findings further. Both the Gomori methenamine silver and periodic acidSchiff stains demonstrated numerous, markedly enlarged blastoconidia and hyphal forms of Candida. Many of these enlarged forms contained a single large, round to oval, clear vacuole occupying the greater part of the blastoconidia (Figure, b). Linear creases transecting the blastoconidia were also observed. Enlarged blastoconidia varied from ovoid and Isospora-like (Figure, c) to those showing broad-based budding similar to that seen with Blastomyces species (Figure, d). Occasionally, giant blastoconidia with multiple buds resembling Paracoccidioides species were also noted. On the periodic and-Schiff stain, the blastoconidial wall stained intensely red, while the central vacuole was light pink and almost colorless.
Morphologically, C albicans presents with 4 distinct forms comprising unicellular yeast cells (blastoconidia), 2 to 8 im in diameter, chains of budding blastoconidia with constrictions termed pseudohyphae, elongated hyphal appendages from blastospore to first constriction (germ tubes), and true hyphae divided by septa. Chlamydoconidia (chlamydospores) are terminal, double-walled cells, 8 to 12 (mu)m in diameter, arising from a hypha or pseudohypha. These cells are only seen in vitro in nutrient-deficient media. In reports in which "chlamydospores" or "chlamydospore-like" cells have been observed in vivo in human or animal tissue, one will note in the photographs accompanying such reports that pseudohyphae arise from the chlamydospore.1-4
Giant blastoconidia of C albicans, characterized as chlamydospores in the literature, have been observed in vivo, usually after administration of a putative inducing agent or as a consequence of host inflammatory response3 (Table). In the early report of Heineman and colleagues,3 chlamydospores were observed histologically in the cardiac vegetation of a diabetic patient with C albicans endocarditis, as well as in kidney abscesses. Although this patient received several antibiotics for Staphylococcus bacteremia (Table), the authors did not comment on the induction of these chlamydospores. Instead, they thought it was related to the pathogenicity of C albicans, which enabled their survival "in the adverse environment of the bodily fluids."
Two additional cases of chlamydospores seen in human tissue (costal cartilage in a patient with systemic lupus erythematosus4 and bronchoalveolar lavage of a patient with acquired immunodeficiency syndrome1) could have resulted from prior administration of an antifungal agent (amphotericin B, nystatin, or ketoconazole).
Giant blastoconidia with germ tubes were also noted by scanning electron microscopy of white scales on the surface of tongues and oral mucosa of patients with chronic mucocutaneous candidiasis.5 Although these authors only commented on their presence, one might assume the administration of an antifungal agent in the management of chronic mucocutaneous candidiasis could have induced giant blastoconidia.
Giant forms of C albicans and C neoformans have occasionally been observed in vivo, either de novo or after administration of an antifungal agent.1,9,10 Giant forms of C neoformans blastoconidia were observed following antifungal treatment, measuring 40 to 50 (mu)m (usual range, 4-- 10 (mu)m) in a lung biopsy9 and up to 60 (mu)m in a brain abscess.10 In both of these instances, however, normally occurring blastoconidia were observed after growth of the original specimens on routine media. Similarly, the Candida isolate in our case reverted back to normal morphology when grown on routine media.
Giant blastoconidia have been demonstrated previously in vitro, after growth on commercially prepared chocolate agar,11 or in histologic sections of gastric mucosa tissue from immunocompromised mice that were previously treated with cyclophosphamide.2
In our case, giant blastoconidia of C albicans were observed both in vivo and in vitro, after culture of the original blood isolate onto commercially prepared chocolate agar supplemented with hemoglobin and IsoVitaleX, known to induce giant blastoconidia.11 Such giant forms were not noted on cultures of our isolate grown on 5% sheep blood or Sabouraud agar.
As noted in the Table, giant blastoconidia of C albicans were observed by Cole et a 12 in histologic sections of the gastric mucosa of orally infected mice after the administration of cyclophosphamide plus cortisone acetate and the antifungal agent cilofungin. Cole and colleagues, who referred to these forms as "chlamydospore-like," attributed the aberrant forms to cyclophosphamide induction. Our case supports this opinion, as the patient had recently received a cyclophosphamide-based chemotherapy regimen for treatment of lymphoma.
Since it is rare to find giant forms of C albicans in vivo, their occurrence in histologic sections may present problems in diagnosis. Individual giant blastoconidia show a spectrum of forms, ranging from blastoconidia with linear creases across their circumference, which closely resemble the giant form of C neoformans,9,10 to elongated ovoid forms resembling Isospora belli.11 On initial impression, the giant forms of Candida may be confused with C neoformans, necessitating a search for circulating cryptococcal antigen. As noted in our case, giant blastoconidia can also present with single, broad-based buds resembling B dermatitidis, with multiple buds resembling Paracoccidioides brasiliensis, or with elliptical shapes. Despite these varied morphologic forms, C albicans was the sole mycotic agent isolated from blood and tissue cultures in our case.
Systemic infection with Candida is a challenging problem in immunocompromised neutropenic patients. Moreover, the presence of giant forms of the organism on histologic sections adds to the challenges inherent in the correct identification of fungal infections in these patients. Such forms of C albicans, as viewed in histologic sections, may be confused with other mycotic agents. Awareness of the in vivo existence of giant forms of C albicans may help focus the differential diagnosis when considering patients with neutropenic fevers. Ultimately, identification of the correct organism will allow for the provision of appropriate treatment.
1. Chabasse D, Bopuchara JP, deGentile L, Chennebault JM. Chlamydospores de Candida albicans observees in vivo chez un patient atteint de SIDA. Ann Biol Clin. 1983;48:817-818.
2. Cole GT, Seshan KR, Phaneuf M, Lynn KT. Chlamydospore-like cells of Candida albicans in the gastrointestinal tract of infected, immunocompromised mice. Can J Microbiol. 1991;37:637-646.
3. Heineman HS, Yunis Ej, Siemienski J, Braude AL. Chlamydospores and dimorphism in Candida albicans endocarditis. Arch Int Med. 1961;168:126.
4. Ho PC, O'Day DM. Candida endophthalmitis and infection of costal cartilages. Br J Ophthalmol. 1981;65:333-334.
5. Wilborn WH, Montes LF. Scanning electron microscopy of oral lesions in chronic mucocutaneous candidiasis. JAMA. 1980;224:2294-2297.
6. Ameglio F, DiGiorgio C, Terzardi C, Gandolfo GM. "Giant cell" production by C. albicans cultured in xylitol. Microbiologica. 1990;13:343-346.
7. Lee W. Chlamydospore-like cells in Candida albicans induced by S-flourocytosine. Can MicrobioL 1973;19:1449-1450.
8. Mittag H. Structural alterations in Candida albicans by caffeine and caffeine salts. Mycoses. 1994;37:337-341.
9. Cruickshank JG, Cavill R, Jelbert JM. Cryptococcus neoformans of unusual morphology. Appi Microbiol. 1973;25:309-312.
10. Love GL, Boyd GD, Greer DL. Large Cryptococcus neoformans isolated from brain abscess. J Clin Microbiol. 1985;22:1068-1070.
11. Bottone EJ, Horga M, Abrams J. "Giant" blastoconidia of Candida albicans: morphologic presentation and concepts regarding their production. Diagn Microbiol Infect Dis. 1999;34:27-32.
Teresa M. Alasio, MD; Patrick A. Lento, MD; Edward J. Bottone, PhD
Accepted for publication February 19, 2003.
From the Departments of Pathology (Drs Alasio and Lento) and Medicine (Infectious Diseases) (Dr Bottone), The Mount Sinai Hospital, New York, NY.
Reprints: Teresa M. Alasio, MD, Department of Pathology, Mount Sinai School of Medicine, Box 1194, One Gustave L. Levy PI, New York, NY 10029 (e-mail: Teresa.firstname.lastname@example.org).
Copyright College of American Pathologists Jul 2003
Provided by ProQuest Information and Learning Company. All rights Reserved