Distinction between bronchioloalveolar carcinoma and hyperplastic pulmonary proliferations: a cytologic and morphometric analysis

Efficacy of Touch Imprint Cytology in Intraoperative Diagnosis of Invasive Mucinous Adenocarcinoma of the Lung: A Case Report and Literature Review

A preoperative diagnosis of the peripheral small lung nodule is often difficult, and an intraoperative frozen section diagnosis (FSD) is performed to guide treatment strategy. However, invasive mucinous adenocarcinoma (IMA) is prone to be overlooked because of the low sample quality and weak atypia. We herein report a case of IMA, in which touch imprint cytology (TIC) revealed diagnostic efficacy. A 74-year-old male with a small, subsolid nodule in the right upper lobe underwent a thoracoscopic wedge resection. A grayish brown, 10 × 7 mm-sized nodule was observed on the cut surface. Intraoperative FSD revealed lung tissue with mild alveolar septal thickening and stromal fibrosis but without overt atypia. Meanwhile, TIC revealed mucus and a few epithelial cells with intranuclear inclusions, which pathologists evaluated as reactive. Finally, focal organizing pneumonia was tentatively diagnosed, and surgery was finished without any additional resection. However, permanent section diagnosis revealed a microinvasive mucinous adenocarcinoma. Nuclear inclusions were confirmed in tumor cells. In the intraoperative setting, TIC may be more advantageous than FSD in observing nuclear inclusions and mucus. Mucinous background and nuclear inclusion on TIC may suggest IMA even if FSD does not suggest malignancy in an intraoperative diagnosis of the peripheral small lung nodule.

Cytological characteristics of histological types of lung cancer by cytomorphometric and flow cytometric analyses using liquid-based cytology materials

BACKGROUND

Distinguishing the histological types of lung cancer is essential for determining treatment strategies in clinical practice. In this study, cytomorphological characteristics and proliferative activities were compared among histological types of lung cancer by cytomorphometric and flow cytometric analyses using liquid-based cytology (LBC) samples.

METHODS

Scraped LBC samples from 73 surgically resected specimens were collected between August 2018 and November 2019. Papanicolaou-stained and paired Ki-67-stained slides were used for cytomorphometric analyses. Another sample for each case was analyzed using a flow cytometric system (LC-1000). The cell proliferation index (CPIx) was calculated to evaluate proliferative activity.

RESULTS

In total, 73 cases, including cases of adenocarcinoma (n = 53), squamous cell carcinoma (n = 14), small cell carcinoma (n = 1), large cell neuroendocrine carcinoma (NEC; n = 3), and pleomorphic carcinoma (n = 2) were evaluated. Small cell carcinoma and large cell NEC were categorized into a single group, NEC. The adenocarcinoma group tended to have a larger nuclear area and longer perimeter than other histological types. The NEC group had a considerably higher Ki-67 labeling index and significantly higher CPIx than other histological types (p = .030). A significant positive correlation was observed between the Ki-67 labeling index and CPIx for all cases (r = 0.362, p = .002).

CONCLUSION

The Ki-67 labeling index and flow cytometric analyses focus on proliferative activity for the distinction of histological types of lung cancer, thereby guiding clinical decision-making.

Cytomorphometric and flow cytometric analyses using liquid-based cytology materials in subtypes of lung adenocarcinoma

BACKGROUND

The histological classifications of invasive lung adenocarcinoma subtypes are considered to predict patient prognosis after surgical treatment. The objectives of this study were to evaluate cytomorphological characteristics and proliferative activities among the histological predominant patterns by performing cytomorphometric and flow cytometric analyses using liquid-based cytology materials.

METHODS

Cytological samples fixed by liquid-based cytology preservatives from 53 surgically-resected lung adenocarcinoma specimens were obtained between August 2018 and November 2019. The Papanicolaou-stained and paired Ki-67-stained slides were analyzed for calculating nuclear morphology (nuclear area, nuclear perimeter and nuclear circularity) and Ki-67 labeling index using software. The cell proliferation index (CPIx) was calculated and cellular information including cell cycle stage of tumor cells was obtained by flow cytometry.

RESULTS

The 53 cases included papillary (n = 29), acinar (n = 8), lepidic (n = 5), and solid (n = 4) subtypes, and invasive mucinous adenocarcinoma (n = 7) were also included. In the lepidic pattern, nuclear area (79.6 ± 28.8 μm² ) and perimeter (34.1 ± 6.1 μm) were relatively larger and longer than those of the other predominant patterns. The Ki-67 labeling index of the solid pattern (27.9 ± 12.5%) was highest compared with those of other predominant patterns. There were statistically significant differences in the lepidic versus solid patterns and the papillary versus solid patterns (p = .013 and p = .039, respectively). The calculated mean CPIx of the lepidic and the acinar patterns were approximately two-fold higher than those of the other predominant patterns.

CONCLUSION

By revealing the differences of cytomorphological characteristics, these methodologies might be used for diagnosing cytopathological materials using digital cytopathology.

"Napoleon Hat" Sign: A Distinctive Cytologic Clue to Reactive Pneumocytes

Various types of acute and subacute lung injury can cause severe reactive pneumocyte atypia, which may mimic malignant proliferations and present a major diagnostic pitfall. This particularly applies to cytologic preparations and frozen sections, where background inflammatory injury may be subtle or not apparent. Although several distinguishing morphologic features of reactive pneumocytes have been suggested, there is significant overlap with neoplastic proliferations. In this article, a highly distinctive but underrecognized feature of reactive pneumocytes is highlighted that can serve as a useful diagnostic clue. The feature refers to the distinctive pinched shape of reactive pneumocytes, for which the author has coined the term "Napoleon hat" sign to draw the analogy with the iconic headwear. The analogy vividly captures the distinctive shape of reactive pneumocytes, and can serve as a useful diagnostic and teaching tool in the interpretation of pulmonary specimens.

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.

Respiratory Tract and Mediastinum

Normal cytology, abnormal and atypical cells, non-cellular components, and infectious cell changes are largely described together with benign, malignant, and neuroendocrine lesions regarding exfoliative and aspiration cytology of the lung. A separate section broadly addresses diagnostic findings and differential diagnoses in bronchoalveolar washings.

The section ‘Fine needle aspiration biopsy of mediastinal disorders’ covers in particular biopsy techniques, accuracy of liquid-based cytology, and the complex lesions of the thymus gland. Cytodiagnostic algorithms of the major benign and malignant pulmonary and mediastinal lesions and their respective differential diagnoses are additionally presented in synoptic setups.

Cytological features of signet-ring cell carcinoma of the lung: comparison with the goblet-cell-type adenocarcinoma of the lung

Signet-ring cell carcinoma (SRCC) and goblet-cell-type adenocarcinoma (GCA) are mucin-producing lung adenocarcinomas. Primary SRCC shows an aggressive clinical course, whereas GCA shows infrequent distant metastasis, but more frequent intrapulmonary metastases resembling lobar pneumonia. To distinguish SRCC from GCA, this study investigated the respective cytological features of these lesions. We selected 10 cases each of SRCC and GCA from the archival imprint smears. We assessed them for the following 10 cytological features. Necrosis/debris was observed in 60% of the SRCC and 90% of the GCA. A mucinous background was observed in 10% of the SRCC and 90% of the GCA. Significant inflammation was observed in none of the SRCC and 80% of the GCA. Stromal cluster was observed in 30% of the SRCC and 70% of the GCA. Nuclear overlapping was observed in 50% of the SRCC and in all of the GCA. Single tumor cells were observed in 80% of the SRCC and 10% of the GCA. Honeycomb-like cluster was observed in none of the SRCC and 80% of the GCA. Prominent nucleolus was observed in 50% of the SRCC and 40% of the GCA. Nuclear membrane irregularity was observed in 70% of SRCC and 60% of the GCA. Nuclear pleomorphism was observed in all of the SRCC and none of the GCA. The cytological features of SRCC were the presence of single tumor cells and nuclear pleomorphism, whereas that of GCA were the presence of abundant mucin and significant inflammation in the background, and a honeycomb-like cluster.

Molecular characteristics of bronchioloalveolar carcinoma and adenocarcinoma, bronchioloalveolar carcinoma subtype, predict response to erlotinib

PURPOSE

We conducted this phase II trial to determine the efficacy of erlotinib in patients with bronchioloalveolar carcinoma (BAC) and adenocarcinoma, BAC subtype, and to determine molecular characteristics associated with response.

PATIENTS AND METHODS

Patients (n = 101) with BAC (n = 12) or adenocarcinoma, BAC subtype (n = 89), were enrolled. All patients received erlotinib 150 mg daily. Epidermal growth factor receptor (EGFR) mutation, EGFR copy number, EGFR immunohistochemistry (IHC), and KRAS mutation status were analyzed in available tumors. The primary end point was response rate (RR).

RESULTS

Overall RR was 22% (95% CI, 14% to 31%). In patients with pure BAC, the RR and median survival were 20% and 4 months, as compared with 23% and 19 months in those with adenocarcinoma, BAC subtype. No patient (zero of 18; 95% CI, 0% to 19%) whose tumor harbored a KRAS mutation responded to erlotinib. Patients with EGFR mutations had an 83% RR (15 of 18; 95% CI, 65% to 94%) and 23-month median OS. On univariate analysis, EGFR mutation and copy number were associated with RR and PFS. EGFR IHC was not associated with RR or progression-free survival (PFS). After multivariate analysis, only EGFR mutation was associated with RR and PFS. No molecular factors were associated with overall survival.

CONCLUSION

Erlotinib is active in BAC and adenocarcinoma, mixed subtype, BAC. Testing for EGFR and KRAS mutations can predict RR and PFS after treatment with erlotinib in this histologically enriched subset of patients with non-small-cell lung cancer (NSCLC). These data suggest that histologic subtype and molecular characteristics should be reported in clinical trials in NSCLC using EGFR-directed therapy.

Cytopathologic factors can predict invasion in small-sized peripheral lung adenocarcinoma with a bronchioloalveolar carcinoma component

BACKGROUND

Patients with noninvasive, small-sized primary adenocarcinomas of the lung have excellent prognosis after lobectomy. Several researchers have suggested that limited resection could be an acceptable alternative for these patients. Therefore, a preoperative or intraoperative judgment of invasiveness would be one of the critical determinants of the surgical procedure in each case. Cytopathologic findings that can distinguish invasive from noninvasive adenocarcinomas remain to be elucidated.

METHODS

Imprint smears were obtained from 60 resected adenocarcinomas with nonmucinous bronchioloalveolar features. Thirteen cytologic factors were evaluated: the presence of necrosis, fibrovascular tissue, proportion of macrophages, the presence of large tumor cell clusters, nuclear grooves, nuclear overlapping, variation in nuclear size, chromatin pattern, presence of a nucleolus, intranuclear inclusions, multinucleated cells, spindle cells, and mitosis. Each factor was examined by univariate analysis for correlation with the presence of histopathologic invasion.

RESULTS

In the univariate analysis, 5 cytologic factors--presence of tumor cell clusters consisting of more than 50 tumor cells (P < .001), nuclear overlapping in more than 3 layers (P < .001), presence of nuclear grooves (P = .007), more than 3-fold variation in nuclear size (P < .001), and 1 mitotic cell per 1000 tumor cells (P = .035)--were associated significantly with invasion. Among these, nuclear overlapping in more than 3 layers (P = .003) and more than 3-fold variation in nuclear size (P = .005) were found to be independent predictive factors for invasion by multivariate analysis.

CONCLUSIONS

Using imprint smears, the presence of invasion in small-sized primary adenocarcinomas of the lung is predictable by the 2 above-mentioned cytologic findings. Imprint smear cytology may effectively aid intraoperative judgement of invasion in cases where frozen section histology is difficult to interpret.

Diagnostic dilemmas in pulmonary cytology

BACKGROUND

Diagnostic difficulties in pulmonary cytology may be compounded by other medical problems, lack of pertinent information, and the presence of rare tumors. In the current study, the authors describe six cases of lower respiratory tract cytology that presented particular diagnostic challenges or pitfalls.

METHODS

Three lung fine-needle aspiration biopsies (FNAB) from three patients, four bronchoalveolar lavages from two patients, and one bronchial washing from one patient, each with histologic confirmation, were reviewed. Cytologic material included direct smears, ThinPrep slides, and cell blocks. Cytologic findings were compared with established cytologic criteria for each final diagnosis.

RESULTS

Two cases with Aspergillus infection that demonstrated reactive atypical cells were misinterpreted as squamous cell carcinoma and nonsmall cell carcinoma. Two cases diagnosed as significant atypia and negative, respectively, subsequently were found to show bronchioloalveolar carcinoma (as well as lymphangioleiomyomatosis, which was suspected clinically) and bronchogenic adenocarcinoma, respectively. One lung FNAB from a patient subsequently confirmed to have bronchiolitis obliterans-organizing pneumonia (BOOP) showed reactive pneumocytes that initially were misinterpreted as being suspicious for carcinoid. These reactive pneumocytes were identified histologically in the area of BOOP. The last case was an FNAB of a well differentiated fetal-type adenocarcinoma, an unusual variant of adenocarcinoma that to the authors' knowledge rarely is described in the cytology literature.

CONCLUSIONS

Cytomorphologic features of lower respiratory tract pathology combined with appropriate clinical information and diagnostic discretion usually allow accurate diagnoses and should decrease both false-positive and false-negative result rates. Clinical information and radiologic findings may be invaluable, but may not always parallel the cytologic diagnosis.

Clinical features of patients with stage IIIB and IV bronchioloalveolar carcinoma of the lung

BACKGROUND

The incidence of bronchioloalveolar carcinoma of the lung (BAC), a pathologically distinct type of nonsmall cell lung carcinoma (NSCLC), appears to be rising. In this study, the authors compared data on the clinical presentation and clinical courses of patients with Stage IIIB and IV BAC with data on other types of NSCLC.

METHODS

The authors collected clinical, radiographic, and pathology information about 28 patients with Stage IIIB and IV BAC and 124 patients with other histologic types of NSCLC.

RESULTS

Twelve of 28 BAC patients (43%) were women, compared with 40 of 124 control patients (32%). Nine (32%) of the patients with BAC had never smoked cigarettes, versus 20 controls (16%) (P = 0.02). Eighteen patients (64%) with BAC had bilateral multilobar or multicentric pulmonary involvement, compared with 13 controls (15%) (P < 0.001). Patients with advanced stage (IIIB and IV) BAC had a median survival of 15 months from the time of diagnosis; for patients with other types of Stage IIIB and IV NSCLC, had a median survival of 10 months (P = 0.01).

CONCLUSIONS

Patients with BAC of the lung have clinical, radiographic, and pathologic characteristics that distinguish them from patients with other types of NSCLC. A greater proportion of women and nonsmokers present with BAC than with other types of NSCLC. Patients with advanced stage BAC are more likely to have bilateral diffuse pulmonary involvement, are less likely to develop brain metastases, and have longer survival than patients with other types of Stage IIIB and IV NSCLC. Further research is warranted to define etiology, molecular abnormalities, and more effective therapeutic interventions.

Cytologic distinction between bronchioalveolar carcinoma and reactive/reparative respiratory epithelium: a cytomorphometric analysis

Cytologically, the distinction between bronchioalveolar carcinoma and reactive/reparative processes of respiratory epithelium can be difficult. Retrospectively, we have identified 11 consecutive cases of bronchioalveolar carcinoma from the cytology files of University Missouri-Kansas City/Truman Medical Center. On average, a combined 5.71 cytologic/histologic procedures were performed before reaching a definitive diagnosis for this group. An additional seven random cases of reactive/reparative respiratory cases of adult respiratory distress syndrome patients were used as a control. Cytomorphometric analysis was performed. The mean average nuclear diameter for the carcinoma group was 13.76 microns and for the reactive/reparative group was 13.29 microns. There was no statistical difference between the two groups (paired student t test, P > .05). It appears from our data that mean nuclear diameter is not a discriminator for the cytologic distinction between bronchioalveolar carcinoma and reactive/reparative respiratory epithelium and that the accepted cytologic parameters of for bronchioalveolar carcinoma are more valid.

Bronchioloalveolar carcinoma: diagnostic pitfalls and immunocytochemical contribution

Because bronchioloalveolar carcinoma (BAC) commonly displays bland cytologic appearance, there is a good potential for misinterpretation. The aim of this study was twofold: one was to identify the most reproducible cytomorphologic features to distinguish BAC from conventional lung adenocarcinoma (CLA) on fine-needle aspiration (FNA), and the other was to investigate the staining characteristics of these two variants of lung carcinoma with P53 tumor suppressor gene immunostain and their potential value in the distinction between the two entities. Cytology records of 13 histologically documented BACs was retrieved: 7 FNA, 3 bronchial washing/bronchial brushing (BW/ BB), and 3 scraping smears of surgical specimens. Two cases had both FNA and BW/BB material. Immunostains for P53 protein, carcinoembryonic antigen (CEA), and Ki67(MIB-1) monoclonal antibodies were performed on 13 BACs (FNA cell blocks and tissue) and on 11 FNA cell blocks of CLA. Cytologically, BAC showed uniform cells with abundant, lacy cytoplasm, and bland, folded nuclei arranged singly, in papillary clusters, and sheets. Immunocytochemically, one BAC and one CLA were technically unacceptable. Of the 12 remaining BAC cases, 10 were reactive with CEA, 9 reactive with Ki67 (> 5%), and 4 reactive with P53. Of the 10 remaining CLAs, 9 were positive with CEA, 9 were reactive with Ki67 (> 5%), and 8 were reactive with P53. We conclude that BAC demonstrates distinctive cytologic features, but difficulty may be encountered with well-differentiated CLA, metastatic adenocarcinoma, and other lesions. Immunocytochemically, CEA and Ki67 do not appear to be discriminate, but P53 may be of value in distinguishing BAC from CLA. Attention to subtle nuclear changes, characteristic grouping, cellular arrangement, and P53 reactivity could enable cytopathologists to accurately diagnose BAC.