RESIDENT CASE STUDIES

August 21, 2003: Case 2  

Table of Contents | List of Diagnoses | Case 1 | Case 2 | Case 3 | Case 4

48 year old female with right lower lobe lung mass

Discussion by Toby Gray, MD

Sclerosing hemangioma of the lung is a benign tumor of uncertain histogenesis, although likely from pulmonary pneumocytes.

Incidence: Rare

Distribution: 80 percent female; average age of presentation is 44 years

Gross Appearance: Typical appearance consists of a circumscribed, round to oval shaped mass. The average diameter is 2.8 cm. The cut surface is tan to gray-red with mottled yellow areas. The majority of cases occur in the lower lobes within the lung parenchyma, but can extend into fissures or to adjacent tissue. Rarely, multiple foci are found.

Microscopic Appearance:

• The microscopic pattern is characterized by four major patterns, of which 90% of the tumors have at least 3
  • The first is a solid pattern consisting of sheets of bland epithelioid tumor cells with little atypia and clear cytoplasm with distinct borders. The nuclei have fine chromatin with inconspicuous nucleoli. 
  • The second is a papillary pattern consisting of papillary-appearing structures, filled with cells as described above, lined by cuboidal eosinophilic cells with prominent nuclei that may have intranuclear inclusions.
  • The third is a sclerotic pattern with increased fibrosis
  • The fourth is a hemorrhagic pattern consisting of dilated cystic spaces filled with blood, giving it a vascular appearance.

Diagnostic Criteria: 

• Primary diagnostic criteria is the presence of the 4 histologic patterns.
• The second diagnostic criteria is the presence of the 2 characteristic cell types described above.

Immunostains:

• These tumors are positive for EMA and most importantly TTF-1
• The tumor cells lining the papillary structures may be cytokeratin positive while the bland tumor cells with clear cytoplasm will be negative. 

Differential Diagnosis:

• Inflammatory pseudotumor, which can appear sclerotic but lacks the other patterns and characteristic cell types.
• Carcinoid, which has more characteristic neuroendocrine cells in specific organoid, trabecular, or rosette patterns.
• Papillary carcinomas such as metastatic renal or thyroid carcinomas, which have more malignant patterns.
• Benign clear cell tumor, which is composed of clear cells similar to the tumor cells, but with glycogen filling these cells and a more delicate vascular pattern throughout.

References:

1. Stephen S Sternberg et al. (Eds): Diagnostic surgical pathology, Volume 1, 3rd edition. Lippincott William& Wilkins.
2. Thomas V. Colby, et al.: Atlas of Tumor Pathology: Tumors of the Lower Respiratory Tract, Fascicle 13, Third series, 1994.