Pulmonary acantholytic squamous cell carcinoma with focal signet ring cell morphology mimicking malignant mesothelioma on fine needle aspiration cytology: a case report

Our plain-English summary of Pulmonary acantholytic squamous cell carcinoma with focal signet ring cell morphology mimicking malignant mesothelioma on fine needle aspiration cytology: a case report, by S.E. Choi, H.S. Park (Cytopathology, 2016).

The study

• Authors: S.E. Choi, H.S. Park
• Journal: Cytopathology
• Published: 2016;27(2):131-3
• Type of article: Case report, Letter
• Cited by: 6 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Summary of the article

The authors, from the Department of Pathology at Gangnam Severance Hospital in Seoul, South Korea, described the cytological features of a lung squamous cell carcinoma (SCC) with both acantholytic and signet ring cell components, and discussed its differential diagnosis. They stated that the signet ring cell variant of SCC had not been reported in the lung. A 64-year-old man was a 35-pack-year ex-smoker with hypertension. A chest X-ray taken during a regular medical examination showed a nodule, and computed tomography showed a 2.8-cm mass with an irregular margin in the left upper lobe. CT-guided fine needle aspiration (FNA) was performed, followed by left upper lobe lobectomy with mediastinal lymph node dissection. The FNA smears showed loose aggregates and scattered round tumour cells. These cells had central nuclei, prominent nucleoli, dense cytoplasm and endoplasmic–ectoplasmic demarcation. Some contained intracytoplasmic vacuoles that were negative for periodic acid-Schiff with diastase. Cell-to-cell opposition with windows, linear arrangement and cell-in-cell engulfment were also seen. All tumour cells were positive for p63 and p40 and negative for TTF-1, napsin-A, calretinin, WT-1 and D2-40. The final diagnosis was acantholytic SCC with signet ring cell features. The cytological differential diagnosis had included poorly differentiated adenocarcinoma, non-keratinizing SCC and intrapulmonary epithelioid malignant mesothelioma. The authors concluded that this tumour's cytological features can resemble epithelioid malignant mesothelioma, and that immunostaining including squamous and mesothelial cell markers may be required to confirm it.

PubMed has no abstract for this study, and the article doesn't print one. We wrote this summary from the full article with the help of AI. It is not the authors' wording.

In plain English

This was a case report, written as a letter to a journal, from a pathology department in Seoul, South Korea. It described a 64-year-old man, a 35-pack-year ex-smoker, whose chest X-ray showed a nodule in the left upper lobe of the lung. A needle sample of the 2.8-cm mass showed loosely grouped and scattered tumour cells, some of which contained vacuoles (small spaces within the cell) that pushed the nucleus to one side. Under the microscope these cells looked like they could be several cancers, including intrapulmonary epithelioid malignant mesothelioma. After the lobe was surgically removed, all tumour cells tested positive for the markers p63 and p40, and none tested positive for TTF-1, napsin-A, calretinin, WT-1 or D2-40. The final diagnosis was acantholytic squamous cell carcinoma of the lung with signet ring cell features. The authors concluded that this tumour can look similar to epithelioid malignant mesothelioma on needle samples, and that special stains for squamous and mesothelial cell markers may be needed to confirm the diagnosis. The article does not mention asbestos exposure.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Case report (letter to the editor)
• Who was studied: One 64-year-old man with a lung nodule in the left upper lobe, studied at the Department of Pathology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea; dates not given
• Exposure: No asbestos or occupational exposure is reported. The patient was a 35-pack-year ex-smoker. The study concerned how a lung cancer can look like mesothelioma on fine needle aspiration cytology.
• Main results:
  • On the needle aspiration sample, occasional tumour cells contained variably sized vacuoles inside the cell that pushed the nucleus to one side
  • On the needle aspiration sample, epithelioid malignant mesothelioma was considered in the differential diagnosis because of the dense cytoplasm and cell-to-cell windows
  • In the removed tumour, all tumour cells were positive for p63 and p40
  • No tumour cells were positive for TTF-1, napsin-A, calretinin, WT-1 or D2-40
  • The final diagnosis was acantholytic squamous cell carcinoma with signet ring cell features
• The authors' conclusion: The authors concluded that the cytological features of acantholytic squamous cell carcinoma with signet ring cells can be similar to those of epithelioid malignant mesothelioma, and that immunostaining with squamous and mesothelial cell markers may be required to confirm this tumour subtype
• Limitations the authors state:
  • The authors stated that, in this case, the two tumours could not easily be told apart from the needle sample cell features alone, and that immunohistochemical study using a cell block would have been helpful

Topics

The National Library of Medicine indexes this study under subjects our site covers: Lung cancer, Mesothelioma.

Medical terms in this study, explained in our Lexicon: Squamous Cell Carcinoma, Malignant Mesothelioma, Cytology, Pathology, Differential Diagnosis, Chest X-Ray, Thyroid Transcription Factor-1 (TTF-1), Calretinin.

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