Role of FNA and Special Stains in Rapid Cytopathological Diagnosis of Pulmonary Nocardiosis

Abstract

Background: Nocardia, a gram-positive aerobic bacillus of the Actinomycetales family, is a significant opportunistic pathogen in immunocompromised individuals. Clinical and radiological features of pulmonary nocardiosis are nonspecific and can be misdiagnosed as tuberculosis, pneumocystis, staphylococcal or fungal infections, or as malignancy. Aspiration cytology with special stains is a quick and effective approach for accurate diagnosis. Materials and Methods: We present 7 cases of pulmonary nocardiosis, admitted to the pathology department in a tertiary-care hospital in Punjab. Clinical findings, immune status, laboratory tests, chest radiographs, and computed tomography scans were reviewed. Cytologically, special stains like 1% Ziehl-Neelsen (ZN), 20% ZN, periodic acid-Schiff (PAS), Grocott methenamine silver (GMS), and reticulin stains were studied along with May-Grünwald Giemsa, Papanicolaou, and hematoxylin and eosin. Results: All the patients were immunocompromised. The radiological changes were nonspecific. Cytomorphology showed acute and chronic inflammatory infiltrates with necrosis. None of the cases showed well-defined granulomas. GMS, modified 1% ZN and, Gordon and Sweet reticulin stains highlighted the delicate filamentous bacteria in all cases. PAS and 20% ZN stain for tuberculous bacilli were uniformly negative. Conclusion: FNAC can provide a quick and accurate diagnosis of nocardiosis and thereby facilitate timely medical management.

Lymphocutaneous Nocardiosis in a Patient With Human Immunodeficiency/Tuberculosis Coinfection

“…can be identified in the fine-needle aspirate smear stained with Papanicolaou stain. Although granulomas are not well formed, multinucleated giant cells and branched filaments were detected under the microscope [8]. A number of conglomerate-like filamentous inclusions were detected as cotton balls [2].…”

Cutaneous nocardiosis with discharging sinus clinically mimicking tuberculosis diagnosed by cytology

“…These are differentiated from most common Mycobacterium tuberculosis bacilli, which are short slender beaded bacilli. Other special stains like silver methenamine stains, particularly Gordon and Sweet's stain and Gram stain are also useful in the diagnosis of Nocardia …”

“…Though there are reported cases of partially acid‐fast anaerobic Gram‐positive bacillus other than Nocardia and Mycobacterium species associated with abscess formation, but the good response to treatment tilts the diagnosis in favor of Nocardia . As culture and biopsy are time consuming and result in undue delay in diagnosis and treatment, FNAC will render a helping hand in rapid, reliable, and cost‐effective diagnostic procedure for identifying these bacteria . Differentiating Nocardia infection from other acid‐fast bacilli like tuberculosis is mandatory to avoid unnecessary antituberculous treatment.…”

“…FNA cytology (FNAC) is the safest, easy, and effective way of tissue diagnosis, especially in lymphocutaneous nocardiosis. 6 Extensive suppurative inflammation and necrosis may be seen in nocardiasis, which makes the identification of bacilli more difficult on routine stains such as MGG, Pap, and hematoxylin and eosin (H&E). 7 But a careful search for negative images and use of special stains aid in the diagnosis of Nocardia.…”

“…11 As culture and biopsy are time consuming and result in undue delay in diagnosis and treatment, FNAC will render a helping hand in rapid, reliable, and cost-effective diagnostic procedure for identifying these bacteria. 6 Differentiating Nocardia infection from other acid-fast bacilli like tuberculosis is mandatory to avoid unnecessary antituberculous treatment.…”