Multivesiculated macrophages: their implication in fine-needle aspiration cytology of lung mass lesions

Adult exogenous lipoid pneumonia: A rare and underrecognized entity in cytology - A case series

Background:

Exogenous lipoid pneumonia (ELP) is a rare benign entity without specific clinical or imaging presentation. Although cytological studies – either bronchoalveolar lavage (BAL) or fine-needle aspiration (FNA) – may be pursued in patients with ELP, a definitive diagnosis is frequently rendered only on histology. The aim of this study is to highlight the cytological features of ELP.

Methods:

A search of cytopathology (CP) and surgical pathology (SP) diagnoses of ELP was conducted. The corresponding clinical and imaging features were obtained, and the morphology, particularly the presence and size of the intracytoplasmic vacuoles and background, was assessed.

Results:

Nine cases of ELP were identified, including eight with corresponding CP and SP. A neoplasm was suspected in three based on imaging, but ELP was not in the differential clinically or radiographically in any. Among the cases, six patients had BALs and three FNAs. All of the samples showed multiple large vacuoles within macrophages with at least some equal to or larger than the size of the cell nucleus. Similar vacuoles were noted extracellularly on smears.

Conclusions:

ELP is typically described in case reports in the clinical or radiological literature. To the best of our knowledge, this represents the largest series of adult ELP in CP. When large vacuoles are present in macrophages in cytology specimens, at least a suspicion of ELP can be suggested to initiate appropriate therapy, identify/remove the inciting agent, and preclude a more invasive procedure.

Amiodarone toxicity presenting as pulmonary mass and peripheral neuropathy: the continuing diagnostic challenge

A 64 year old man receiving long term amiodarone treatment presented with dyspnea, cough, and weight loss. Radiographs and computed tomography showed a lung mass with associated multiple pulmonary nodules. Biopsies of the pulmonary mass showed foamy histiocytes without malignant cells. However, findings on FDG-PET scan were consistent with a malignant tumour. These findings on computed tomography and PET scan and the unusually late resolution of the pulmonary lesions after withdrawal of amiodarone treatment posed a challenging diagnostic problem.

Amiodarone lung toxicity in a cardiac transplant candidate initially diagnosed by fine-needle aspiration: Cytologic, histologic, and electronmicroscopic findings

A cardiac transplant candidate with ischemic cardiomyopathy developed bilateral small parenchymal opacities in lower lobes of the lung. A fine-needle aspiration (FNA) was performed that revealed changes characteristic of amiodarone toxicity. Subsequently performed lung biopsies and electron microscopic studies confirmed the initial FNA diagnosis. The patient has been successfully transplanted with marked improvement in his clinical findings. This is the first case of amiodarone lung toxicity where the diagnosis was initially suggested based on the FNA findings. We also describe the clinical, cytological, histological, and electron microscopic (EM) findings of amiodarone-related pulmonary toxicity and provide a review of the literature.

Is amiodarone an underrecognized cause of acute respiratory failure in the ICU?

Amiodarone is a commonly used anti-arrhythmic agent, with well-recognized chronic toxicity. Less well known is amiodarone's potential to cause acute lung damage, which can be severe or, occasionally, life-threatening. Lungs that have already been exposed to physical insults, such as the lungs of patients undergoing cardiac surgery, are particularly susceptible to acute pulmonary toxicity (APT). Unfortunately, cardiac surgery is one of the clinical scenarios in which amiodarone is most commonly used. After reviewing the data, and even in the context of difficulties and discrepancies in the existing literature, we contend that there is sufficient evidence of amiodarone's potentially serious side-effect profile in surgical ICU patients to advise continued caution in its use with this severely ill patient group. We suggest that amiodarone has a potentially important, though underrecognized, role in inducing an APT/ARDS in some patients, such as those undergoing cardiac surgery. We also provide a hypothesis to explain the mechanism by which amiodarone causes lung damage.

Rhodococcus equi and cytomegalovirus pneumonia in a renal transplant patient: diagnosis by fine-needle aspiration biopsy

Rhodococcus equi is a common cause of pneumonia in animals. Human infection is rare. Increasing number of cases are being reported in immunosuppressed individuals mostly associated with HIV infection, but also in solid organ transplant recipients and leukemia/lymphoma patients. We report on an adult male who developed pneumonia and gastroenteritis 4 mo after receiving a renal transplant. CT scan of the lungs showed a dominant 2.5-cm upper lobe lung mass and smaller bilateral nodules. He underwent a diagnostic bronchoscopy with fine-needle aspiration biopsy of the largest lung nodule. Smears showed histiocytic granulomatous inflammation, foamy macrophages, and acute inflammatory exudate. Scattered foamy macrophages displayed intracellular coccobacilli identifiable on Diff-Quik stain. A few cells with changes suggestive of viral inclusions were identified. Cytomegalovirus (CMV) immunostain was positive in the cell block sections. Lung cultures grew R. equi. To the best of our knowledge, this is the first report of coinfection with R. equi and CMV.

Detection of the 20-kDa virulence-associated antigen of Rhodococcus equi in malakoplakia-like lesion in pleural tissue obtained from an AIDS patient

A malakoplakia-like lesion was detected in a pleural biopsy from an AIDS patient presenting clinical and radiologic features of pneumonia. Cultures of bronchoalveolar lavage and pleural fluid evidenced Rhodococcus equi as the causative agent of pleuro-pulmonary infection. Immunochemical characterization of the R. equi isolate showed the presence of a strain similar to the ATCC 33704 reference strain presenting the capsular antigen of serotype 4, and the intermediate virulence-associated antigen of 20-kDa. Histopathology of the patient's pleural biopsy showed plaques of macrophages interspersed with lymphocytes, and intracytoplasmic cocci and bacilli in macrophages, which were variably acid-fast positive. Immunohistochemistry of cocci, bacilli and their degradation products resulted strongly positive when stained with a mouse monoclonal antibody (MAb) produced against the 20-kDa antigen. This finding could have important implications for the pathogenicity of R. equi for human beings, since we do not know yet all the factors involved in the formation of malakoplakia. Indeed, the results obtained in the present study, taken together with the results obtained for pigs inoculated with R. equi strains of intermediate virulence (Madarame et al. 1998), raise the possibility that most strains presenting the 20-kDa antigen may be capable of inducing malakoplakia. If this hypothesis is confirmed by immunohistochemical analysis of human pulmonary malakoplakia cases due to R. equi, the detection of this antigen may be extremely helpful in the diagnosis and treatment of such patients. This is the first report of R. equi infection in human beings that suggests a relationship between pleural malakoplakia and the virulence-associated antigen of 20-kDa.