Original contributionsMesothelioma with clear cell features: an ultrastructural and immunohistochemical study of 20 cases
Introduction
A well-known characteristic of tumors derived from the serosal membranes is their ability to grow in a wide variety of histologic patterns. Based on their light microscopic appearance, mesotheliomas have been subdivided into epithelioid, sarcomatoid, mixed epithelioid and sarcomatoid (biphasic), and desmoplastic subtypes. Although epithelioid mesotheliomas most frequently exhibit a tubulopapillary, tubular, or solid pattern, on rare occasions they may present other histologic patterns, including deciduoid, pleomorphic, small cell, signet-ring, and clear cell [1], [2], [3], [4]. Because general pathologists are less aware of the latter patterns, diagnostic difficulties may be encountered, especially in biopsy specimens, because these unusual morphological variants of mesothelioma can be confused with a variety of other neoplastic conditions. Although the presence of a few scattered cells or small clusters of cells exhibiting clear cell cytoplasm is not a rare finding in mesotheliomas, epithelioid mesotheliomas predominantly composed of cells having clear or finely vacuolated cytoplasm are uncommon and only a few individual case reports have been published [4], [5], [6]. The purpose of this study is to report a series of 20 mesotheliomas presenting clear cell morphology, investigate the causes of the clearing, discuss the differential diagnosis of these tumors, and make pathologists more aware of the existence of this variant of epithelioid mesothelioma.
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Materials and methods
The 20 mesothelioma cases with clear cell morphology were obtained from the files of the Department of Pathology at The University of Texas MD Anderson Cancer Center. The specimens consisted of 13 pleural biopsies, 1 abdominal biopsy, 4 cytology specimens (2 pleural fluids, 1 peritoneal fluid, and 1 fine needle aspiration), and 6 extrapleural pneumonectomy specimens.
Tissue specimens were fixed in 10% buffered formalin and processed routinely for light microscopy. Cytology specimens were
Clinical findings
Eighteen patients were men and 2 were women ranging in age from 55 to 86 years (mean, 67 years). There was a history of asbestos exposure in 12 patients and smoking in 9. The mesotheliomas originated in the pleura in 17 cases and in the peritoneum in 3. Seven patients received chemotherapy alone. Six underwent extrapleural pneumonectomy, with 1 also receiving chemotherapy, and another receiving radiation therapy. Treatment information was not available in the remaining patients. Five patients
Discussion
The results of the present investigation indicate that the prominent cytoplasmic clearing sometimes observed in mesotheliomas is not caused by a single factor but is the result of a variety of factors that can occur singly or in combination. The most frequent cause of this cytoplasmic clearing is the accumulation of large amounts of intracytoplasmic glycogen. Although not an uncommon finding in mesotheliomas, clear or predominantly clear mesotheliomas in which the cytoplasmic clearing is
Acknowledgment
The author thanks Ms Janet Quiñones and Mr Mannie Steglich for technical assistance and Ms Asuncion Moroi for secretarial assistance.
References (35)
The diagnostic utility of immunohistochemistry in distinguishing between mesothelioma and renal cell carcinoma: a comparative study
hum path
(2004)- et al.
Lipid-rich diffuse malignant mesothelioma: a case report
hum path
(2000) - et al.
Clear cell variant of medullary carcinoma of the thyroid
hum path
(1985) - et al.
Vacuolated cell mesothelioma of the pericardium resembling liposarcoma: a case report
hum path
(2000) Value of mesothelin immunostaining in the diagnosis of mesothelioma
Mod Pathol
(2003)- et al.
Expression of calretinin and other mesothelioma-related markers in thymic carcinoma and thymoma
hum path
(2003) - et al.
Ultrastructural features of diffuse malignant mesotheliomas
hum path
(1998) - et al.
Pathology of malignant mesothelioma
Histopathology
(1997) Pleural disease
Epithelial mesothelioma with deciduoid features: report of four cases
Am J Surg Pathol
(2000)
Clear cell mesothelioma
Ultrastruct Pathol
Foamy cell mesothelioma
Histopathology
Unusual clear cell variant of epithelioid mesothelioma
Arch Pathol Lab Med
The immunohistochemical diagnosis of mesothelioma: a comparative study of epithelioid mesothelioma and lung adenocarcinoma
Am J Surg Pathol
Glycogen-rich mesothelioma
Ultrastruct Pathol
Malignant peritoneal mesothelioma with massive foamy cells: codfish roe–like mesothelioma
Acta Pathol Jpn
Papillary carcinoma of the thyroid, oxyphil cell type, “clear cell” variant: a light and electron microscopic study
Am J Surg Pathol
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2019, Human PathologyCitation Excerpt :Clear cell mesothelioma, also called glycogen-rich or foamy mesothelioma, is considered a variant of epithelioid MM. It is a rare entity that was first described by Ordoñez et al [2,5] in 1996, with only isolated cases reported so far in the pleura [2,3,5-7], peritoneum [2,8,9], and testis [10]. Given the rarity of such entity, the final diagnosis of clear cell mesothelioma, in our case, was reached after excluding more common intra-abdominal tumors with clear cell morphology that entered the differential diagnosis, which included carcinomas arising from upper or lower gastrointestinal tract, pancreas, adrenal, kidney, liver and Müllerian system/primary peritoneum, or metastatic carcinomas from breast or lung origins.
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2017, Diagnostic Gynecologic and Obstetric PathologyMalignant peritoneal mesothelioma, clear cell variant, in a female and its differentiation from clear cell carcinoma
2017, Pathology Research and PracticeCitation Excerpt :While both tumors are characterized by a papillotubular or solid growth pattern, clear cell carcinoma generally features greater nuclear atypia than malignant mesothelioma and has a characteristic hobnail appearance [8,9]. According to a literature review, the solid to sheet-like pattern of tumor cell proliferation seen in the clear cell subtype of malignant mesothelioma contrasts with the mixed papillary, tubular, and solid growth pattern of clear cell carcinoma [2–7]. In addition, malignant mesotheliomas characteristically show diffuse extension to the pleural or peritoneal cavity, whereas clear cell carcinomas generally form bulky masses in the abdominal cavity [6,7].