Malignant pleural mesothelioma with scalp, cerebellar, and finger metastases: a rare case.

Abstract: Malignant pleural mesothelioma (MPM) is a rare and asbestosis-associated tumor. MPM commonly invades locally, mostly in the lung, heart, pericardium, chest wall, and vertebrae. Distant metastasis of MPM is very rare. Here we report a patient with MPM who presented with multiple unusual distant metastases. The patient's thorax tomography demonstrated right-sided, irregularly-thickened pleura with nodular masses and invasion of the chest wall into the subcutaneous area. The patient underwent biopsy for a subcutaneous mass in the right anterior chest wall. Pathologic examination revealed a malignant mesenchymal tumor. During follow-up, he suffered from a painful nodule on the scalp and nodules on the fingers, as well as weakness in his right arm. Cranial magnetic resonance imaging illustrated a 1 cm nodule in the left cerebellar hemisphere. Histopathologic examination of the biopsy from the nodule on the scalp revealed a typical mixed type of MPM, with calretinin, vimentin and creatine 5/6 positivity. Distant metastases can be seen in MPM and a biopsy of metastatic regions can yield the diagnosis.

Key Words: mesothelioma, distant metastases

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Malignant pleural mesothelioma (MPM) is an uncommon tumor of mesothelial lining cells, and is mostly seen in patients with asbestos exposure. There is a 20 to 40 year latent period after initial exposure to asbestos. MPM commonly spreads locally and mostly to the lung, heart, pericardium, chest wall, and vertebrae. (1) Distant metastasis of MPM is very rare. Brain, cerebellum, spleen, bone marrow, prostate, thyroid, orbit, uterus, pelvis, tonsil, tongue, mandibular alveolus are reported sites for metastasis. (2-9) To our knowledge, there is only one report in the literature of scalp metastasis. (10) Here we report a patient with MPM who presented with multiple unusual distant metastases.

Case Report

A 47-year-old male was admitted to our hospital with the complaints of chest pain and dyspnea. His symptoms were present for 6 months and had progressively worsened. His medical history was noncontributory except for a smoking history of 20 packs per year. His initial vital signs were normal and oxygen saturation was 93%. Physical examination was unremarkable. Laboratory studies revealed normal levels after a complete blood count, liver-renal function tests, and urine analysis. Erythrocyte sedimentation rate was elevated (80 mm/h). His chest x-ray illustrated diffuse pleural thickening on the right pleura and thorax tomography revealed irregularly-thickened pleura with nodular masses at the posterior right lung field, invasion of the chest wall and a subcutaneous area was noticed. The patient underwent a biopsy for the subcutaneous mass in the right anterior chest wall. Pathology report was malignant mesenchymal tumor; no special finding for MPM was present. In the follow-up, he suffered from a painful nodule on the left parieto-occipital scalp. Histopathologic examination of the biopsy from the nodule revealed a typical mix type of MPM, with calretinin, vimentin and creatine 5/6 positivity (Figs. 1 and 2). In his routine physical examination, new onset motor deficit was noticed in his right arm. Cranial magnetic resonance imaging illustrated a 1 cm nodule in the left cerebellar hemisphere (Fig. 3). In the beginning we planned 6 cycles of vinorelbine 25 mg/[m.sup.2] on the 1st, 8th, and 15th days. After the second cycle his chest pain disappeared and the primary lesion had not regressed. Before the 4th cycle, a new metastatic nodule on the second finger of his left hand was noticed. The chemotherapy was stopped. He was followed with supportive care, but died 6 months after diagnosis.

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Discussion

Malignant mesothelioma originates from the mesothelial cells, most commonly from the pleura, but also from the pericardium, peritoneum, tunica vaginalis of testis and ovarium. (11-13) Typical clinical findings of the patients are chest pain and dyspnea. (14) The distant metastases are rare and caused by lymphatic and hematogenous spread to different sites. To the best of our knowledge, there has been only one report in the literature about scalp metastasis and no report about finger metastasis.

Histopathological diagnosis of mesothelioma is difficult due to the morphologic resemblance to other neoplasms, such as adenocarcinoma. Therefore, immunohis-tochemistry has an important role in the confirmation of the diagnosis. In this patient, the biopsy of the nodule on the scalp showed typical histopathologic features of mixed type MPM and the accurate diagnosis could be made from the metastatic lesion.

[FIGURE 2 OMITTED]

[FIGURE 3 OMITTED]

The treatment of MPM is generally palliative. Standard treatment modalities are surgery (pleurectomy/decortication), chemotherapy and radiotherapy. There are many chemotherapy regimens including pemetrexed, doxorubicin, cisplatin, gemcitabine, methotrexate, vinorelbine, and capecitabine. Our patient received chemotherapy with vinorelbine. After the second cycle of chemotherapy, the patient's pain disappeared, although he had progressive disease before the fourth cycle of chemotherapy.

Conclusion

Scalp, central nervous system and finger metastases are rare in MPM. The case was interesting not only for the rare site of the metastasis, but also for the confirmation of pathology from the metastatic site. We emphasize that unexpected distant metastases can be seen in MPM and occasionally primary diagnosis can be made by the biopsy of the metastatic regions.

References

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9. Hefer T, Danino J, Joachims HZ, et al. Metastatic malignant mesothelioma to the tonsil. Otolaryngol Head Neck Surg 1997;116 (6 Pt l):684-688.

10. Bazex A, Migueres J, Dupre A, et al. [Scalp metastases of pleural mesothelioma.] Bull Soc Fr Dermatol Syphiligr 1969;76:99-101.

11. Berkowitz RK, Longley J, Buchness MR, et al. Malignant mesothelioma: diagnosis by skin biopsy. J Am Acad Dermatol 1989;21:1068-1073.

12. Ordonez NG, Smith JL. Peritoneal malignant mesothelioma with multiple distant skin metastases. Arch Dermatol 1983;119:827-830.

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14. Dunnil MS. Pleural mesothelioma. Eur J Respir Dis 1984;65:159-161.

We don't see things as they are, we see them as we are.
--Anais Nin

Asiye Kanbay, MD, Kivilcim Ipek Oguzulgen, Ass. Prof, Can Ozturk, Prof, Leyla Memis, Prof, Sedat Demircan, Ass. Prof, Can Kurkcuoglu, MD, Nalan Akyurek, MD, and Cuneyt Kurul, MD

From the Departments of Pulmonary Medicine, Pathology, and Chest Surgery, Gazi University School of Medicine, Ankara, Turkey.

Reprint requests to Asiye Kanbay, MD, 35. sokak 81/5 06490, Emek, Ankara, Turkey. Email: [e-mail]

Accepted April 20, 2006.

RELATED ARTICLE: Key Points

* Unexpected distant metastases can be seen in malignant pleural mesothelioma.

* Primary diagnosis can be made by the biopsy of the metastatic regions.

* Distant metastasis of malignant pleural mesothelioma is very rare.