Clear Cell Tumor of the Lung Immunohistochemical and Ultrastructural Evidence of Melanogenesis
University of Washington Seattle, Seattle, Washington, United States American Journal of Surgical Pathology
(Impact Factor: 5.15).
08/1991; 15(7):644-53. DOI: 10.1097/00000478-199107000-00005
Clear cell tumors of the lung (CCTL) are rare neoplasms of uncertain differentiation. A previous study of eight CCTL demonstrated a lack of epithelial features, but their exact nature remained unknown. In the current study of nine CCTL, immunohistochemistry using preliminary enzymatic digestion showed strong reactivity with the antimelanocytic markers HMB-45 (seven cases) and HMB-50 (six cases) and focal positivity for S-100 (nine cases), neuron-specific enolase (three cases), synaptophysin (one case), and Leu-7 (one case). Staining for cytokeratin, epithelial membrane antigen, chromogranin, and glial fibrillary acid protein was uniformly negative. Frozen-section immunoreactivity for vimentin and the antimelanocytic monoclonal preparation NKI/BETEB was noted in the one CCTL for which snap-frozen tissue was available. Ultrastructural examination of three glutaraldehyde-fixed CCTL showed rare neoplastic cells containing the full spectrum of melanosomes in two, one of which also contained neurosecretory-type granules. Aberrant melanosomal forms were identified in the third case. Melanosomes were not identified in the remaining five CCTL studied from formalin- or paraffin-retrieved material. The findings indicate that CCTL exhibits melanocytic differentiation. This feature may be of considerable value in distinguishing CCTL from other clear cell neoplasms.
Available from: PubMed Central
- "A total of 56 CCTL cases (including the present case) were reviewed [2,4,6-27]. The collected data included patient age, gender, symptoms, and tumor location, contour, and density. "
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ABSTRACT: Clear cell tumor of the lung is a rare and benign pulmonary tumor; only sporadic cases have been reported. Here, we report the case of a 38-year-old man with recurrent cough, blood-streaked sputum and left chest pain. A chest computed tomography scan showed a round, homogeneous pulmonary mass in the left lower lobe, which exhibited intense heterogeneous enhancement in the arterial phase and homogeneous in the delay phase after injecting a contrast agent. The patient underwent a fine-needle aspiration biopsy and was diagnosed as having a benign clear cell tumor of the lung. The clinical presentation and radiographic investigation of this tumor are summarized in this paper to recognize this rare disease. Interestingly, we found some differences with previously reported cases.
Available from: Ghada Esheba
- "All these tumors share a distinctive cell type, the perivascular epithelioid cell or 'PEC' (which has no known normal tissue counterpart). The perivascular epithelioid cell (PEC) is a ''novel'' cell type showing morphologic, immunohistochemical, ultrastructural, and genetical distinctive features, such as an epithelioid appearance with a clear to granular cytoplasm, a round to oval, centrally located nucleus and an inconspicuous nucleolus, and a typical perivascular location      . Immunohistochemically , PEC expresses myogenic and melanocytic markers, such as HMB-45, Melan-A/Mart1, smooth muscle actin and, less commonly, desmin  . "
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ABSTRACT: Although angiomyolipoma (AML) is a relatively rare entity, it is the most common benign mesenchymal neoplasm of the kidney.
To highlight the clinicopathological characteristics of AML and to assess the role of Human Melanoma Black-45 (HMB-45), Melan-A, smooth muscle actin (SMA), S-100 and cytokeratin in its diagnosis.
The study included 15 cases of AML. Clinical and radiological data were retrieved from the archival files and all cases were subjected to a histopathological evaluation as well as immunohistochemical staining for HMB-45, Melan-A, SMA, S-100, and cytokeratin.
AML was more common in females (female:male=4:1), the mean age was 53.9±6.45years. 60% of patients were symptomatic while the remaining 40% were asymptomatic. A statistically significant relationship was found between size of the tumor and the presence of the symptoms (P=0.02). Patients with tumor size less than 4cm were asymptomatic, while those with tumor size larger than 4cm had different symptoms. Thirteen cases were classic AML, while 2 cases were epithelioid AML. Classic AML demonstrated admixture of fatty tissue, thick-walled blood vessels, and smooth muscle, while epithelioid AML was composed mainly of epithelioid cells and contained no fat. HMB-45 was positive in all cases of AML (100%), Melan-A was positive in 13/15 (87%) while SMA was positive in 11/15 (73%) of AML with variable staining intensity. All cases of AML were negative for S-100 and cytokeratin.
AMLs have characteristic clinicopathological and immunohistochemical features and their recognition is crucial for proper diagnosis and treatment.
Available from: rjme.ro
- "The expression of melanocytic markers is not aberrant but due to the presence of pre-melanosomes in the cells of PEComas      . There is evidence that cells that are derived from the neural crest can express many of the markers mentioned above, under certain environmental influence. "
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ABSTRACT: The perivascular epithelioid cell (PEC) has been proposed to be the proliferating cell type in a group of tumors known as PEComas. The histogenesis of PEComas is one of the most mysterious aspects of pathology. Hypothesis on its precursor are many, including a cell from blood vessel walls or the myoblast. In the current report, we review many morphologic, clinical, ultrastructural, molecular and genetic aspects that support the hypothesis of an origin of PEComas from the neural crest.
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