Respiratory cytology: Differential diagnosis and pitfalls

A distinctive cytomorphological feature of interstitial pneumonia-related lung adenocarcinoma: The potential issues and solutions in practical diagnosis

BACKGROUND

The cytological features of interstitial pneumonia (IP)-related lung adenocarcinoma (LADC) have not been clearly described. This study aimed to describe its cytomorphological features, uncover potential problems in practical cytological diagnosis, and provide possible solutions.

METHODS

Bronchial brushing cytology samples from 40 IP-related LADC cases (the IP group) and 110 control cases (LADC unrelated to IP; the non-IP group) were analyzed. All patients underwent surgery after brushing cytology, and their histopathological subtypes were determined. The authors reviewed the cytological features and focused particularly on cytoplasmic mucin production.

RESULTS

In the IP group, neoplastic cells with cytoplasmic mucin were detected at a significantly higher frequency (44.4% [8 of 18] vs. 6.3% [4 of 64]), and most of them were invasive mucinous adenocarcinomas (IMAs). Twenty-two of the 40 LADC cases in the IP group failed to be judged as "malignant/positive" (thus, they were judged to be "equivocal and/or negative"). The frequency of equivocal and/or negative judgments was 55.0% (22 of 40) in the IP group and 41.8% (46 of 110) in the non-IP group. The cytological diagnosis of IMA was difficult because it showed only slight nuclear atypia. Therefore, the authors examined the immunocytochemical expression of hepatocyte nuclear factor 4α (HNF4α), a diagnostic marker for IMA. As a result, four of the six cases that were judged to be equivocal in the IP group showed positive signals and could be retrospectively judged as malignant/positive.

CONCLUSIONS

The cytological diagnosis of IP-related LADC may be more difficult because of the larger proportion of IMA. Immunocytochemistry for HNF4α can be used to improve diagnostic confidence in IP-related LADC.

Busulfan associated pulmonary toxicity: A benign mimic of squamous cell carcinoma diagnosed in a bronchoalveolar lavage specimen

An uncommon case of iatrogenic cellular changes associated with busulfan therapy in a bronchoalveolar lavage of a 65-year-old woman who underwent bone marrow transplantation is presented and discussed. Chemotherapeutic changes are presented, and pitfalls discussed.

Can cytology reliably subtype non-small cell lung carcinomas?

Cytology specimens play an important role in the diagnosis and predictive testing of lung cancer. While morphological characterisation of small cell and non-small cell lung carcinomas (NSCLC) on cytology is possible, further subtyping of NSCLC into adenocarcinoma and squamous cell carcinoma morphology is also mandatory in the current era of personalised medicine. Notably, cytology specimens in different forms (fine needle aspiration, exfoliative, and cell block) with or without immunocytochemistry are reliable sources for accurate diagnosis of adenocarcinoma and squamous cell carcinoma as evidenced by numerous studies present in the literature. However, there are instances where subtyping of NSCLC based on morphology alone is challenging on cytology samples, especially non-cell block preparations. In this paper, we will discuss current concepts, advances, and challenges of subtyping NSCLC in cytology specimens.

"Single-cell pattern" of adenocarcinoma cells in effusion cytology: Morphologic challenges of lung cancer

BACKGROUND

Lung adenocarcinomas present as tight clusters and three-dimensional balls in effusion specimens. Unlike carcinomas of breast and stomach where singly lying malignant cells are seen in effusion samples, lung adenocarcinomas usually show cohesive morphology. This single-cell pattern may also be confused with reactive mesothelial cells. We studied the frequency of pulmonary adenocarcinoma with single-cell pattern cytomorphology in pleural effusion specimens.

MATERIALS AND METHODS

All cases reported as either suspicious or positive for malignancy on pleural effusion cytology (PFC) over the past 1 year were retrieved. The clinical details were obtained from requisition forms. Cases with predominant single-cell pattern, clinically suspicious of carcinoma lung were segregated. These were de-stained and immunocytochemistry (ICC) for TTF-1 was performed.

RESULTS

Of 103 cases reported as either suspicious or positive for malignancy on PFC, 29 had a predominant single-cell pattern. Of these, 13 (44.8%) were primary lung carcinoma. The rest were metastasis from ovary (5; 17.2%), breast (2; 6.9%), stomach (2; 6.9%), lymphoma (1; 3.5%), and Ewing's sarcoma (1; 3.5%). Five (17.2%) were those with unknown primary. All cases of lung carcinoma were positive for TTF-1 ICC.

CONCLUSION

Single-cell pattern of pulmonary adenocarcinoma is commoner than popularly believed. This pattern may be difficult to differentiate from carcinoma cells of other sites as well as from reactive mesothelial cells. A high degree of suspicion is therefore needed to perform relevant ICC to clinch the correct diagnosis.

Pulmonary small cell carcinoma: Review, common and uncommon differentials, genomics and management

Lung cancer is the leading cause of cancer-related death worldwide. It is divided into sub-categories based upon morphology, immunostaining pattern, biology, molecular profile, and/or treatment options. Up until the early 2000s when driver mutations with targeted therapies were identified in a subset of adenocarcinomas, the most critical distinction of lung carcinomas was driven by differences in treatment between small cell carcinoma (SCC) and nonsmall cell lung carcinoma (NSCLC). The distinction between SCC and NSCLC remains critical in the 21st century for management, especially for advanced stage cancer. In the vast majority of cases, morphological features are sufficient to separate SCC from other types of lung cancers. In some instances, however, cytomorphological features and immunohistochemical overlap with other tumors, limited sample availability, and/or crush artifact pose diagnostic challenges. The aim of this review is to highlight salient features of SCC and ancillary studies to distinguish it from common and uncommon potential mimickers, as well as provide updates in genomics and management.

Cytologic features and diagnostic value of PeriView FLEX transbronchial needle aspiration targeting pulmonary nodules

BACKGROUND

Transbronchial needle aspiration (TBNA) of peripheral lung nodules can be difficult with conventional devices due to their limited flexibility. A promising new technology for accessing these lesions is the PeriView FLEX TBNA device, which has a flexible spiral-grooved needle. The present study reports the unique cytologic features, diagnostic value, and potential pitfalls of PeriView FLEX TBNA specimens.

METHODS

This study retrospectively evaluates 113 consecutive cases of lung nodules sampled using the PeriView FLEX device with radial endobronchial ultrasound guidance.

RESULTS

PeriView FLEX specimens were satisfactory for evaluation in 111 of 113 cases (98%). A diagnosis of malignancy was made on 64 specimens (57%), with 100% specificity and 70% sensitivity for malignancy. In 4 cases, the PeriView FLEX sample was the only specimen from bronchoscopy that was diagnostic of malignancy. Of the 64 PeriView FLEX specimens with malignant cells, 58 (91%) were adequate for immunohistochemistry and 44 (69%) were adequate for molecular genetic testing. Potential pitfalls were largely ameliorated through education regarding the unique features of PeriView FLEX samples, such as the expected abundance of anthracotic pigment and the paucity of lymphocytes.

CONCLUSIONS

TBNA using the PeriView FLEX device to sample pulmonary nodules contributed to the diagnostic value of bronchoscopy and tended to provide sufficient tissue for ancillary studies. Many of the possible pitfalls may be avoided through consideration of the unique cytologic features associated with this novel sampling method.

The approach of scratch-imprint cytology: Is it an alternative to frozen section for intraoperative assessment of pulmonary lesions?

To address the diagnostic performance of scratch-imprint cytology (SIC), in this study we compared intraoperative diagnoses of pulmonary lesions between SIC and frozen section histology (FSH) for accuracy with respect to the final pathological diagnosis. We histologically divided 206 pulmonary lesions (resected surgically) into two groups (benign and malignant) and compared each intraoperative diagnosis by SIC and FSH with the final pathological diagnoses. We also examined the radiological existence of pure ground-glass opacity (GGO) nodules in each group. The diagnostic sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 91.5%, 100%, 100%, 63.6%, and 92.6%, respectively for SIC, and 98.2%, 100%, 100%, 92.1% and 98.5%, respectively, for FSH. Thus, we concluded that diagnosis by SIC is reliable for malignancy, but not for benign lesions. All pure GGO nodules (19; 9.2%) were noninfectious and malignant with a high accuracy of FSH diagnosis (100%), in comparison with those of low accuracy with a SIC diagnosis (57.9%). SIC can be an appropriate intraoperative diagnostic tool where multiple cytotechnologists observe intraoperative SIC preparations scratched evenly across the whole lesion including the peripheral area of the mass.

The value of cell block based on fine needle aspiration for lung cancer diagnosis

BACKGROUND

Computed tomography (CT)-guided percutaneous lung fine needle aspiration (FNA) is a convenient method to obtain samples from pulmonary lesions. FNA has a lower rate of complications than the use of a core needle biopsy, but is more difficult for the diagnosis of cytological samples. We use cell block (CB) and immunocytochemistry (ICC) to improve the accuracy of cytological diagnoses based on CT-guided percutaneous lung FNA.

METHODS

We collected 526 cytological samples obtained using CT-guided percutaneous lung FNA at Shanghai Pulmonary Hospital from May 2015 to October 2015. CBs were created from these samples, and ICC was performed to help the further histological classification and confirmation of tumor as primary or metastatic. An automated Ventana ALK with clone D5F3 was used to identify ALK fusion protein.

RESULTS

After assessment of the CBs, 32 (6.08%) diagnoses of suspected malignancy were reduced to 10 (1.90%) such diagnoses (P<0.05), and 161 (30.61%) cases of non-small-cell lung carcinoma (NSCLC) were reduced to 33 (6.27%) cases (P<0.05) after their division into specific subtypes. We also diagnosed eight (1.52%, P<0.05) cases of metastatic carcinoma of the lung that were difficult to diagnose by cytological smear alone. Six (3.73%) of 161 NSCLC cases exhibited ALK rearrangement.

CONCLUSIONS

CB and ICC are useful for accurate cytological diagnosis using CT-guided percutaneous lung FNA. These approaches are valuable for providing individualized treatment and prognostic evaluations with minor complications.

Non-specific benign pathological results on transthoracic core-needle biopsy: how to differentiate false-negatives?

OBJECTIVES

To determine the negative predictive value (NPV) of non-specific benign results from cone-beam CT (CBCT)-guided transthoracic core-needle biopsy (TTNB) and identify predicting factors for false-negative for malignancies.

METHODS

From January 2009-December 2011, 1,108 consecutive patients with 1,116 lung lesions underwent CBCT-guided TTNB using an 18-gauge coaxial cutting needle. Among them, 226 patients with 226 TTNBs, initially diagnosed as non-specific benign, were included in this study. The medical charts, radiological or pathological follow-ups were reviewed to classify false-negative and true-negative results and to identify which variables were associated with false-negatives.

RESULTS

Of 226 lesions, 24 (10.6%) were finally confirmed as malignancies and 202 (89.4%) as benign, of which the NPV was 89.4% (202/226). Multivariate analysis revealed that part-solid nodule (PSN) (odds ratio (OR), 3.95; P = 0.022), a biopsy result of 'granulomatous inflammation' (OR, 0.04; P = 0.022), and exact location of needle tip within targets (OR, 0.37; P = 0.045) were significantly associated with false-negatives among initial non-specific benign biopsy results.

CONCLUSION

The NPV of the non-specific benign biopsy was 89.4%. PSN was a significant positive indicator, but a biopsy result of 'granulomatous inflammation' and exact location of needle tip within targets were significant negative indicators for false-negatives.

KEY POINTS

• The negative predictive value of the non-specific benign biopsy was 89.4%. • A part-solid nodule is a significant predictor for false-negative biopsy (OR = 3.95). • Pathological diagnosis of granulomatous inflammation is a robust indicator for 'true-negatives'. • Identifying needle tip within target lesions is a significant predictor for 'true-negatives'.

Bronchial wash cytology: A study on morphology and morphometry

Background:

Bronchial wash cytology of lung lesions is a non/minimally invasive procedure utilized for diagnosis of pulmonary lesions.

Aim:

The aim of this study was to evaluate the efficacy of bronchial wash cytology in the diagnosis of bronchopulmonary lesions and assess the role of morphometry in categorizing dysplastic/malignant lesions.

Materials and Methods:

All cases of bronchial wash cytology received from January 2006 to June 2010 were retrieved and reviewed. Cases with adequate clinical data or a subsequent biopsy were selected for the study and cytodiagnosis was correlated with available clinical details. Morphometry was done on alcohol fixed hematoxylin and eosin stained cytosmears using computer assisted Image Pro software.

Results:

One hundred and seventy-six cases of the 373 cases of bronchial cytology received were included for the study. Bronchial wash cytology technique showed high specificity. Cytohistopathology correlation showed 62.06% concordance rate. Cells from normal epithelium, reactive atypia, neoplastic atypia, squamous metaplasia, non-small cell and small cell carcinoma showed a mean nuclear diameter of 7.4 μm, 11.7 μm, 13.9 μm, 13.0 μm, 10.7 μm, and 17.7 μm, respectively, which was statistically significant with P < 0.05. Multiple comparisons between various groups using analysis of variance and Bonferroni tests also showed remarkable statistical significance.

Conclusions:

Bronchial wash cytology has low sensitivity in detecting pulmonary lesions. It can be of value in patients with contraindication for biopsy. Morphometry can be a useful adjunct to cytomorphology, especially in situations where biopsy is contraindicated.

Granulomatous inflammation and organizing pneumonia: Role of computed tomography-guided lung fine needle aspirations, touch preparations and core biopsies in the evaluation of common non-neoplastic diagnoses

Background:

Fine-needle aspirations (FNAs) and core biopsies (CBs), with or without touch preparations (TPs), are performed to characterize pulmonary lesions. Although a positive (P) or suspicious report is sufficient for further management, the significance of unsatisfactory (U), negative (N) and atypical (A) cytological diagnoses remains uncertain. The aims of the study were to correlate U, N and A cytological diagnoses with histological and/or clinical/radiological follow-up and evaluate the utility of FNAs, TPs and CBs.

Materials and Methods:

We performed a retrospective search and examined 30 consecutive computed tomography-guided transthoracic U, N and A lung FNAs (n = 23) and TPs (n = 7) with surgical pathology (SP) (n = 17) and/or clinical/radiological follow-up (n = 13) and compared them to 10 SP-confirmed P FNAs, which served as controls.

Results:

The 30 FNAs and TPs were from 29 patients. All 6 U specimens were scantly cellular. Granulomas, the most common specific benign cytological diagnosis, were evident in 8 (of 13) and 7 (of 11) N and A cytology cases, respectively. Histology corroborated the presence of granulomas identified on cytology. Organizing pneumonia was the second leading benign specific diagnosis (5/17), but it was rendered on histology (n = 5) and not FNAs or TPs. Evaluation of the A cases revealed that type II pneumocytes were the source of “atypical”, diagnoses often associated with granulomas or organizing pneumonia and lacked 3-D clusters evident in all P cases.

Discussion:

U, N and A FNAs and TPs lacked 3-D clusters seen in carcinomas and were negative on follow-up. Granulomas and organizing pneumonia were the most common specific benign diagnoses, but the latter was recognized on histology only. In the absence of a definitive FNA result at the time of on-site assessment, a CB with a TP containing type II pneumocytes increases the likelihood of a specific benign diagnosis.

Cytological diagnosis of typical carcinoid on bronchoscopic brush smears in an HIV-positive patient

We report a case of typical carcinoid of the lung in a 60-year-old human immunodeficiency virus (HIV)-positive man diagnosed on brush cytology smears. Bronchial carcinoids are rare tumors, accounting for 1% to 2% of all lung tumors. Although the exact incidence in HIV-infected individuals is not known, the paucity of their documentation in the literature indicates that they may be equally rare. Cytological diagnosis on brush smears is rarely documented as the tumor is covered with mucosa and cellular yield is often not good. In this case, bronchial brushings showed distinctive cytological features of typical carcinoid. The awareness of its characteristic cytological features and differential diagnosis is required for an accurate diagnosis. Clinical awareness that non–acquired immunodeficiency syndrome (AIDS)-defining cancers can also occur in HIV-infected individuals in the context of the prolonged survival in the antiretroviral era is equally important. This case emphasizes the clinical importance of a broad differential diagnosis for lung lesions in HIV-positive patients.