Peritoneal Malignant Mesothelioma Metastasizing to Lymph Node in Young Male—a Case Report

Abstract

Peritoneal malignant mesothelioma is an uncommon neoplasm with a poor prognosis. We hereby report a case of a 20-year-old male, first diagnosed on biopsy with axillary lymph node metastasis. He presented with abdominal pain and axillary lymphadenopathy, with no history of asbestos exposure. CECT showed peritoneal thickening and ascites. Ascitic fluid cytology showed reactive morphology. The diagnosis of metastatic deposits of malignant mesothelioma was made on histopathology and confirmed by immunohistochemistry. Tumor cells were immune-reactive for CK 5/6, calretinin, D2-40, and WT1 and negative for TTF1, CK 20, and CD 3. This case report has two important highlights—(i) unusual presentation with axillary lymph node metastasis leading to diagnostic dilemma in a young male with no asbestos exposure history and (ii) confirmatory diagnostic role of IHC in Peritoneal malignant mesothelioma.

Introduction

Malignant mesothelioma is a fatal neoplasm of mesothelial surfaces of body cavities, occurring mostly in elderly men with occasional cases in young adults [1]. Peritoneal malignant mesothelioma (PMM) accounts for only 10–20% of all malignant mesothelioma, majority being pleural mesotheliomas [2]. Peritoneal malignant mesothelioma presents with nonspecific manifestations, most commonly abdominal discomfort and distention, digestive disturbances, and weight loss. Occasionally, the patients may present with distant metastasis. However, systemic lymphadenopathy is an exceedingly rare initial presentation of this disease [3, 4].

Case Description

A 20-year-old male, student presented with abdominal pain and axillary lymphadenopathy, with no history of asbestos exposure or any previous chronic disease. On examination, a single, hard, mobile, right axillary lymph node measuring 4 × 1.8 cm in size was palpated. CECT showed peritoneal thickening and ascites. Ascitic fluid cytology showed reactive morphology.

Excision biopsy of lymph node revealed distortion of the lymph node architecture with massive dilatation of sinuses by sheets of round cells with abundant pinkish cytoplasm having vesicular nuclei and prominent nucleoli. Increased mitotic activity along with areas of necrosis was also identified (Fig. 1).

Fig. 1.

The lymph node architecture distortion with extensive sinus enlargement

Differential diagnosis of metastatic deposits of malignant mesothelioma and carcinoma was considered. Immunohistochemistry revealed tumor cells with diffuse immunoreactivity for CK 5/6, calretinin, D2-40, and WT1 and negative for TTF1, CK 20, and CD 3 (Fig. 2).

Fig. 2.

Results of immunohistochemistry tumor cell identification

So, metastasis from the lung, thyroid, GIT, and lymphoma was ruled out and a confirmatory diagnosis of PMM was reported. The patient was referred to a tertiary oncology center but was reluctant to pursue treatment because of financial constraints.

Discussion

Peritoneal malignant mesothelioma (PMM) accounts for only 10–20% of all malignant mesothelioma, majority are pleural mesotheliomas. Our querycase is of a 20-year-old young male with no history of asbestos exposure. PMM manifests commonly in elderly males, but literature states cases in young patients [1, 5]. However, asbestos exposure is the most common pathogenetic factor, other less frequent alternative etiologies like mineral fiber types (erionite, fluoro-edenite), carbon nanotubes, therapeutic radiation, chronic pleural inflammation, germline mutations/deletions contribute, and most mesotheliomas not clearly attributable to asbestos exposure are spontaneous (idiopathic) [6–8].

Peritoneal malignant mesothelioma is usually diagnosed at an advanced stage, probably because of non-specific disease manifestations in the early stage. Clinical presentation is quite variable, depending on the extent of tumor spread within the abdominal cavity. Accumulation of ascites and growth of tumor masses result in abdominal distension in 30–80% of patients. Abdominal pain is the second most common presenting symptom in approximately 27–58% of cases. Occasionally, the patients may present with distant metastasis. Systemic lymphadenopathy, however, is an exceedingly rare initial presentation with 13 cases being reported in the literature. In four of those cases, systemic lymphadenopathy was the only clinical manifestation [9–11]. Axillary lymph node metastasis is reported in only one case in a case of pericardial mesothelioma [10]. CT scan may reveal a solid, heterogeneous, soft-tissue mass with irregular margins and demonstrate high contrast between the enhanced tumor and the non-enhanced ascites. Peritoneal and mesenterial thickening are also frequent findings. Histologically, PMM is divided into epithelioid, sarcomatoid, and biphasic subtypes. Among these, epithelioid is the most common, representing 75–90% of reported cases, and is associated with the best prognosis. Immunohistochemistry is a must for diagnosis as histopathology suggests differential diagnosis and is not confirmatory [11, 12].

Conclusion

This case report highlights a very unusual presentation of PMM presenting with axillary lymph node metastasis leading to diagnostic dilemma in a young male with no asbestos exposure history. Immunohistochemistry plays the final confirmatory diagnostic role in peritoneal malignant mesothelioma.

Data Availability

Data cannot be shared openly to protect study participant privacy.

Declarations

Conflict of Interest

The authors declare no competing interests.