Introduction
Malakoplakia (MPL) is a rare inflammatory disease of unknown etiology. The name has been derived from Greek malakos means soft, plakos-plaque. 1 It is known to affect both genders (especially women) and mostly people of younger age group.2 MPL is a chronic granulomatous disease and also precedes or accompanied by an immunosuppressive state especially in old age and also can occur before. It is a benign condition and also self-limiting with mostly having good prognosis.2 The disease was first described by Von Hansemann in 1901, and then a year later Leonor Michaelis and Carl Gutmann declared the morphological characteristics of the disease.3, 4
Being a rare histiocytic disease it is known to occur in all systemic organs and known to occur commonly in the genitourinary tract, particularly bladder followed by gastrointestinal tract
It is known to co-exist with underlying malignant conditions especially in the genitourinary system. Though the etiopathogenesis of MPL is not fully known, impairment in bactericidal activity of macrophages had been widely accepted as an underlying mechanism in pathogenesis.
The definite diagnosis of MPL is usually arrived by histopathological studies of the affected tissue. Malakoplakia in eye and orbit region are extremely rare. To our knowledge only three cases of malakoplakia involving the eye had been reported that too among elderly patients.5 Literature states that Malakoplakia in orbital region is present with ulceration could carry away the clinician towards infective conjunctivitis and at instance ophthalmic tumours.
In the present case report, we encountered a middle-aged male presenting with swelling in left eye, otherwise asymptomatic case.
Case History
A thirty-nine years old male patient came with a complaint of swelling in left eye since 1 year. There was no history of watering or discharge from eyes.
Figure 2
Microscopic appearance showing mixed population of inflammatory cells and sheets ofhistiocytes in aggregates, H&E4X
Figure 3
Microscopic appearance shows histiocytes and inflammatory cells, Michaelis Guttman bodies. H&E (oil immersion)
Figure 4
Pas stain: a,b: Microscopic rounded basophilic intracytoplasmic inclusions that contain calcium and iron deposits, H&E (oil immersion)
Ultrasound procedure was done which revealed a scleral nodule in the left eye.
Laboratory test done showed total count of 7700 cells/cu.mm with 45.9% neutrophils, 38.9% lymphocytes, 10.9% eosinophils, 0.8% basophils, 3.5% monocytes and platelet count of 281000/cu.mm and hb of 12.0 g/dl.
On Local Examination of left eye
Vision was normal, the posterior segment was normal and there was a firm tender nodule with overlying dilated conjunctival and episcleral vessel and minimal chemosis. Clinically infective conjunctivitis was suspected and due to the persistent nature of the swelling, left eye lamellar excision of scleral nodule was performed under LA for histopathological evaluation.
Discussion
Malakoplakia is a rare granulomatous disease that occurs commonly in the urinary tract, also seen in gastrointestinal tract, central nervous system, tongue and female genital tract.1, 2 Grossly, malakoplakia can present as soft tan yellow plaques and nodules or even extensive bands. The lesion is usually solitary but also can be multiple. 3, 4
The intracellular accumulation of partially degraded bacteria leads to development of granulomatous reaction and the pathognomic Michelis Gutman bodies(MG)- calcified, basophilic, intracellular inclusions that stains positive for periodic acid Schiff stain which often appear as targetoid or owl’s eye lesions.6 Because the bactericidal activity of macrophages is impaired, it may lead to infections, sepsis and bacteremia. Patients with malakoplakia are often found to be infected with bacteria which is Escherichia coli.7, 8 Other bacterias in patients include Klebsiella pneumoniae, Aerobacter aerogenes, Rhodococcus equi, Mycobacterium intracellulare, Corynebacterium species, Proteus species, Pseudomonas species, Acinetobacter species, Staphylococcus species, Streptococcus species, and Enterococcus species. 7
Histologically, it shows collections of histiocytes with granular eosinophilic cytoplasm accumulated beneath the surface epithelium (Figure 2). Few cells show round, concentrically layered intracytoplasmic inclusions known as Michaelis–Gutmann bodies(characteristic of malakoplakia)(Figure 3). The MG bodies are basophilic and demonstrated by periodic acid–Schiff(PAS) positive and stain for iron and calcium(Figure 4 a,b). The granulomatous process was accompanied by chronic inflammatory infiltrate (lymphocytes and plasma cells) and also acute inflammatory infiltrate (neutrophils).Stains used are PAS, Perls (iron) stain and von Kossa (calcium) for Michaelis-Gutmann bodies. The treatment depends on medical therapy in the form of multiple antibiotics that are concentrated in macrophages that is quinolone and trimethoprim-sulfamethoxazole. 8
Malakoplakia needs to be differentiated from other infectious diseases, neoplastic and reactive/reparative processes. Infections to consider include tuberculosis, Whipple's disease, lepromatous leprosy, fungus such as Cryptococcus, and parasites like leishmaniasis. Special stains for microorganisms and tissue culture are necessary to differentiate. 9
Conclusion
To conclude, Malakoplakia is a chronic inflammatory disease though very rare, still known to occur in an otherwise asymptomatic patient. Malakoplakia should be kept as one of the differential diagnosis by the pathologist while dealing with ophthalmic specimen in middle aged eye swelling especially when many histiocytic aggregates are encountered on histology. Clinical suspicion of malakoplakia should be raised in non-immunocompromised patients presenting with asymptomatic eye swelling.
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