Final Diagnosis -- Sclerosing Pneumocytoma

FINAL DIAGNOSIS

Sclerosing Pneumocytoma

Follow-up:
Six monthly x-ray of the chest shows no evidence of recurrence of disease or metastasis.

DISCUSSION

Sclerosing Pneumocytoma (formerly called Pulmonary Sclerosing Hemangioma) is a relatively uncommon benign neoplasm of lung. It is a biphasic tumor that exhibits four major morphological patterns: solid, papillary, hemangiomatous, and sclerotic [1]. The name is a misnomer since prior studies have proven that this tumor is of epithelial cell origin. There are only a few case reports of Sclerosing Pneumocytoma encountered in FNA samples [2]. Many of these cases were misdiagnosed because of the variable cytomorphological features and because they closely mimic primary epithelial and mesenchymal lung tumors [3, 4, 5] In particular, they may mimic primary lung adenocarcinoma, well-differentiated carcinoid tumors, solitary fibrous tumors, or inflammatory myofibroblastic tumors. Metastatic tumors with papillary structures such as renal cell carcinoma or papillary thyroid carcinoma should also be considered in the differential.

The immunohistochemical panel is often helpful in making the diagnosis of Sclerosing Pneumocytoma. The tumors are comprised of biphasic cells including surface cells and stromal round cells. Both the surface and round cells are diffusely positive for TTF-1 and EMA. However, Cytokeratin AE1/AE3 is positive only in the surface cells. On the contrary, progesterone receptor is only positive in the round cells [6].

Though, single and multiple lymph node metastasis has been reported with Sclerosing Pneumocytoma [7,8], the complete surgical excision of the tumor is curative.

REFERENCES

  1. Liebow AA, Hubbell DS. Sclerosing hemangioma (histiocytoma, xanthoma) of the lung. Cancer. 1956;9:53-75.
  2. Hill GS, Eggleston JC. Electron microscopic study of so-called "pulmonary sclerosing hemangioma". Report of a case suggesting epithelial origin. Cancer. 1972 Oct;30(4):1092-1106.
  3. Wojcik EM, Sneige N, Lawrence DD, Ordóñez NG. Fine-needle aspiration cytology of sclerosing hemangioma of the lung: Case report with immunohistochemical study. Diagn Cytopathol. 1993;9:304-9.
  4. Chow LT, Chan SK, Chow WH, Tsui MS. Pulmonary sclerosing hemangioma. Report of a case with diagnosis by fine needle aspiration. Acta Cytol. 1992;36:287-92.
  5. Ng WK, Fu KH, Wang E, Tang V. Sclerosing hemangioma of lung: A close cytologic mimicker of pulmonary adenocarcinoma. Diagn Cytopathol. 2001;25:316-20.
  6. Zeng J, Zhou F, Wei XJ, et al. Sclerosing hemangioma: A diagnostic dilemma in fine needle aspiration cytology. Cytojournal 2016;13:9. 10.4103/1742-6413.180783
  7. Pokharel S, Dhillon SS, Ylagan L, et al. Sclerosing Pneumocytoma with Lymph Node Metastasis. J Thorac Oncol 2016;11:1802-4. 10.1016/j.jtho.2016.06.005
  8. Yano M, Yamakawa Y, Kiriyama M, et al. Sclerosing hemangioma with metastases to multiple nodal stations. Ann Thorac Surg 2002;73:981-3. 10.1016/S0003-4975(01)03122-8

Contributed by Swikrity Upadhyay Baskota, MBBS, MD and Liron Pantanowitz, MD



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