Introduction: Pulmonary spindle cell and mesenchymal lesions are paradox for pathologists due to their rarity, overlapping morphology, and differentials ranging from benign to malignant lesions, and correct diagnosis is essential due to major treatment implications. This study highlights the role of fine-needle aspiration cytology, clot core biopsy, and immunohistochemistry in diagnosis of spindle cell lesions in lung, thus playing a key role in patient management. Methods: It is a retrospective study of lung FNA with predominantly spindle and mesenchymal cells from 2015–2020 which were classified cytomorphologically into spindle, epithelioid, small round cell, and biphasic, and IHC panels are applied accordingly. FNA from mediastinum and chest wall was excluded. Results: 60 cases of lung FNA with spindle and mesenchymal cells were identified and included 6 benign and 54 malignancies which included 24 primary pulmonary malignancies and 30 metastases. Most common primary malignancy was sarcomatoid carcinoma, and most common metastasis was malignant peripheral nerve sheath tumour. FNA was paucicellular in 7 cases and was reported as benign in 7 cases and malignant in 46 cases. There were two false-negative cases. One case of pulmonary blastoma was reported as inflammatory pseudotumour on cytology, and other case of chondrosarcoma was reported as chondroid tumour. Sensitivity and specificity of FNA in distinguishing benign lesions and malignancies were 93.8% and 100%, respectively. Conclusion: FNA along with clot core biopsy/cell block and IHC plays a pivotal role in the subsequent pathway taken for diagnostic or therapeutic management of these patients without the need for second sampling or trucut biopsies in a low resource setting.

Lindeman NI, Cagle PT, Aisner DL, Arcila ME, Beasley MB, Bernicker EH, et al. Updated molecular testing guideline for the selection of lung cancer patients for treatment with targeted tyrosine kinase inhibitors: guideline from the college of American pathologists, the international association for the study of lung cancer, and the association for molecular pathology. Arch Pathol Lab Med. 2018 Mar;142(3):321–46.
Hummel P, Cangiarella JF, Cohen JM, Yang G, Waisman J, Chhieng DC. Transthoracic fine-needle aspiration biopsy of pulmonary spindle cell and mesenchymal lesions: a study of 61 cases. Cancer. 2001 Jun 25;93(3):187–98.
Moreira AL. Evolution of guidelines for respiratory cytology by the Papanicolaou society of cytopathology. Diagn Cytopathol. 2020;48(10):867–9.
Casali PG, Abecassis N, Aro HT, Bauer S, Biagini R, Bielack S, et al. Soft tissue and visceral sarcomas: ESMO-EURACAN Clinical Practice Guidelines for diagnosis, treatment and follow-up. Ann Oncol. 2018 Oct 1;29(Suppl 4):iv51–67.
Bean SM, Baker A, Eloubeidi M, Eltoum I, Jhala N, Crowe R, et al. Endoscopic ultrasound-guided fine-needle aspiration of intrathoracic and intra-abdominal spindle cell and mesenchymal lesions. Cancer Cytopathol. 2011 Feb 25;119(1):37–48.
Lin O, Zerbini MC, Latorre Mdo R, Saigo PE. Cytologic analyses of spindle-cell lesions of the thorax and retroperitoneum. Diagn Cytopathol. 2002 Dec;27(6):343–9.
Chebib I, Hornicek FJ, Nielsen GP, Deshpande V. Cytomorphologic features that distinguish schwannoma from other low-grade spindle cell lesions. Cancer Cytopathol. 2015 Mar;123(3):171–9.
Boland JM, Colby TV, Folpe AL. Intrathoracic peripheral nerve sheath tumors-a clinicopathological study of 75 cases. Hum Pathol. 2015 Mar;46(3):419–25.
Nokes BT, Baumann CP, Cummings KW, Larsen BT, Cartin-Ceba R, Swanson KL. Intrathoracic ganglioneuroma presenting as an endobronchial mass. Respir Med Case Rep. 2017 Aug 24;22:209–11.
Hughes JH, Young NA, Wilbur DC, Renshaw AA, Mody DR; Cytopathology Resource Committee, College of American Pathologists. Fine needle aspiration of pulmonary hamartoma: a common source of false-positive diagnoses in the College of American Pathologists Interlaboratory Comparison Program in Nongynecologic Cytology. Arch Pathol Lab Med. 2005;129(1):19–22.
Creager AJ, Madden CR, Bergman S, Geisinger KR. Aneurysmal bone cyst: fine-needle aspiration findings in 23 patients with clinical and radiologic correlation. Am J Clin Pathol. 2007 Nov;128(5):740–5.
Song W, Suurmeijer AJH, Bollen SM, Cleton-Jansen AM, Bovee JVMG, Kroon HM. Soft tissue aneurysmal bone cyst: six new cases with imaging details, molecular pathology, and review of the literature. Skeletal Radiol. 2019;48(7):1059–67.
Wakely P Jr. Pulmonary spindle cell lesions: correlation of aspiration cytopathology and histopathology. Ann Diagn Pathol. 2001 Aug;5(4):216–28.
Travis WD. Sarcomatoid neoplasms of the lung and pleura. Arch Pathol Lab Med. 2010 Nov;134(11):1645–58.
Travis WD, Al-Dayel FH, Bubendorf L, Chung JH, Rekhtman N, Scagliotti GV. Small diagnostic samples. 5th ed. In: Lokuhetty D, White VA, Cree IA, editors. WHO classification of tumours of the lung, pleura, thymus and heart. Lyon, France: International Agency for Research on Cancer; 2021. p. 29–36.
Choi HS, Seol H, Heo IY, Jung CW, Cho SY, Park S, et al. Fine-needle aspiration cytology of pleomorphic carcinomas of the lung. Korean J Pathol. 2012;46(6):576–82.
Hiroshima K, Dosaka-Akita H, Usuda K, Ogura S, Kusunoki Y, Kodama T, et al. Cytological characteristics of pulmonary pleomorphic and giant cell carcinomas. Acta Cytol. 2011;55(2):173–9.
Etienne-Mastroianni B, Falchero L, Chalabreysse L, Loire R, Ranchère D, Souquet PJ, et al. Primary sarcomas of the lung: a clinicopathologic study of 12 cases. Lung Cancer. 2002 Dec;38(3):283–9.
Zaccarini DJ, Deng X, Tull J, Maciak C, Valente AL, Zhang S. Expression of TLE-1 and CD99 in carcinoma: pitfalls in diagnosis of synovial sarcoma. Appl Immunohistochem Mol Morphol. 2018 Jul;26(6):368–73.
Zhang Y, Wessman S, Wejde J, Tani E, Haglund F. Diagnosing synovial sarcoma by fine-needle aspiration cytology and molecular techniques. Cytopathology. 2019 Sep;30(5):504–9.
Klijanienko J, Caillaud JM, Lagacé R, Vielh P. Cytohistologic correlations in 56 synovial sarcomas in 36 patients: the Institut Curie experience. Diagn Cytopathol. 2002 Aug;27(2):96–102.
Chebib I, Jo VY. Application of ancillary studies in soft tissue cytology using a pattern-based approach. Cancer Cytopathol. 2018 Aug;126(Suppl 8):691–710.
Wakely PE Jr, Ali SZ, Bishop JA. The cytopathology of malignant peripheral nerve sheath tumor: a report of 55 fine-needle aspiration cases. Cancer Cytopathol. 2012 Oct 25;120(5):334–41.
Domanski HA, Akerman M, Rissler P, Gustafson P. Fine-needle aspiration of soft tissue leiomyosarcoma: an analysis of the most common cytologic findings and the value of ancillary techniques. Diagn Cytopathol. 2006 Sep;34(9):597–604.
Shalini CS, Joseph LD, Abraham G, Prathiba D, Rajendiran S. Cytologic features of pulmonary blastoma. J Cytol. 2009 Apr;26(2):74–6.
Jayaram G, Sthaneshwar P. Fine-needle aspiration cytology of phyllodes tumors. Diagn Cytopathol. 2002 Apr;26(4):222–7.
Costa J, Klijanienko J, Desjardins L, Cassoux N, Machet MC, Pacquement H. Fine needle aspiration in intraocular metastasis from pleuropulmonary blastoma. A case report and a review of the literature. Diagn Cytopathol. 2017 Feb;45(2):156–60.
Gelven PL, Hopkins MA, Green CA, Harley RA, Wilson MM. Fine-needle aspiration cytology of pleuropulmonary blastoma: case report and review of the literature. Diagn Cytopathol. 1997;16(4):336–40.
Ghosh M, Islam N, Ghosh A, Chaudhuri PM, Saha K, Chatterjee U. Pleuropulmonary blastoma developing in a case of misinterpreted congenital pulmonary airway malformation: a case report. Fetal Pediatr Pathol. 2018 Oct;37(5):377–86.
Zhao M, Rao Q, Wu C, Zhao Z, He X, Ru G. Alveolar soft part sarcoma of lung: report of a unique case with emphasis on diagnostic utility of molecular genetic analysis for TFE3 gene rearrangement and immunohistochemistry for TFE3 antigen expression. Diagn Pathol. 2015;10:160.
Rekhi B, Rao V, Ramadwar M. Revisiting cytomorphology, including unusual features and clinical scenarios of 8 cases of alveolar soft part sarcoma with TFE3 immunohistochemical staining in 7 cases. Cytopathology. 2021 Jan;32(1):20–8.
Xu Y, Zhou T, Yu W, Zarrin-Khameh N. Fine-needle aspiration of alveolar soft part sarcoma: histologic correlation and aberrant CD68 expression. Diagn Cytopathol. 2019 Feb;47(2):114–20.
Wakely PE Jr. Cytopathology of classic type epithelioid sarcoma: a series of 20 cases and review of the literature. J Am Soc Cytopathol. 2020 May–Jun;9(3):126–36.
Rekhi B, Singh N. Spectrum of cytopathologic features of epithelioid sarcoma in a series of 7 uncommon cases with immunohistochemical results, including loss of INI1/SMARCB1 in two test cases. Diagn Cytopathol. 2016 Jul;44(7):636–42.
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