Indian Journal of Pathology and Microbiology

: 2020  |  Volume : 63  |  Issue : 1  |  Page : 144--145

Cellular cardiac myxoma: New histopathological subtype?

Sudheer Arava1, Devajit Nath2, Rajashekar Palleti3, Ruma Ray1,  
1 Department of Pathology, All India Institute of Medical Sciences, New Delhi, India
2 Department of Pathology, SSPH and PGTI, Noida, Uttar Pradesh, India
3 Department of CTVS, All India Institute of Medical Sciences, New Delhi, India

Correspondence Address:
Sudheer Arava
Department of Pathology, All India Institute of Medical Sciences, New Delhi - 110 029

How to cite this article:
Arava S, Nath D, Palleti R, Ray R. Cellular cardiac myxoma: New histopathological subtype?.Indian J Pathol Microbiol 2020;63:144-145

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Arava S, Nath D, Palleti R, Ray R. Cellular cardiac myxoma: New histopathological subtype?. Indian J Pathol Microbiol [serial online] 2020 [cited 2022 Sep 25 ];63:144-145
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A 35-year-old male presented to the cardiac outpatient with a history of gradual increase in dyspnea. Echocardiographic examination revealed the presence of a mass-like lesion on both right and left atrial cavity. Clinically and radiologically first possible differential considered was biatrial myxoma. The patient was planned for surgery and both the atrial masses were removed and sent for histopathological examination. Systemic examination was unremarkable. Patient was clinically improved after the short follow-up. Long-term follow-up is not available.

The right atrial mass was measuring 3.5 × 2 × 2 cm and the left atrial mass was measuring 3 × 2 × 2 cm. On gross examination, both had a smooth lobulated surface. On cutting open, left atrial mass showed classical macroscopic features of cardiac myxoma like glistening surface with areas of hemorrhage and cystic changes. But the right atrial mass was firm to hard in consistency. Although cut surface showed glistening appearance, other degenerative changes like cystic change and areas of hemorrhage were not obvious. Multiple sections were processed from both the masses. On microscopic examination [Figure 1], left atrial mass showed typical features of cardiac myxoma having dispersed stellate-shaped cells with focal trabecular and vasoformative architecture of lepidic cells in the background of abundant extracellular bluish mucopolysaccharide matrix. The areas of secondary degenerative changes were also noted (cystic change, hemorrhage, mild chronic inflammation, hemosiderin-laden macrophages). Whereas sections from right atrial mass showed more cellularity with many stellate- and oval-shaped cells arranged in singles, small clusters, and in a trabecular pattern. Vasoformative areas were also observed. However, the background mucopolysaccharide matrix was minimal. Secondary degenerative changes were not identified except for mild patchy lymphocytic infiltration in the stroma. Special stain (Alcian blue periodic acid Schiff-ABPAS) revealed minimal matrix vacuolation around the stellate cell and vasoformative clusters. The proliferative index of the tumor (KI 67 index) was low. Further immunohistochemical staining pattern (calretinin and CD 31 immunostain) was like that of any other classical myxoma. Mitosis or necrosis was not identified. Because of these observations, we called this type of myxoma as “cellular cardiac myxoma” as a new histopathological entity.{Figure 1}

Myxomas are the most common primary tumors of the heart in adults.[1],[2] Their cell of origin is thought to be from a pluripotent cell in the subendocardial location.[3] They can arise from any of the cardiac chambers; however, the left atrium is the most common site.[4] On gross examination, myxomas show a smooth lobulated or papillary surface. The presence of papillae is more dangerous as it can cause frequent systemic embolization.[5] Grossly they are usually soft to little firm in consistency and may show hemorrhagic discoloration on their surface. On microscopic examination, the most common histopathological feature includes the presence of stellate- to oval-shaped cells laying in an abundant extracellular mucoid matrix, hence, the name myxoma. The tumor cells (lepidic cells) may show an arrangement in single cells pattern, trabecular pattern or in a vasoformative pattern.[6] Depending upon the type of cell predominant they are subdivided as 1) single-cell predominant, 2) trabecular predominant, and 3) vasoformative predominant type. Cardiac myxomas commonly show areas of secondary degenerative changes like variable-sized cystic spaces, areas of hemorrhage, and fibrin exudation. Stromal inflammatory cell infiltrate and hemosiderin-laden macrophages are also commonly noted. Occasionally, cardiac myxomas also show the areas of calcification and bone formation with hematopoietic component and Gamna-Gandy-bodies-like structure as that of the chronic congestive spleen. Rarely, myxomas also show the presence of a benign glandular component of intestinal morphology and they are called a glandular cardiac myxoma.[2] Few myxomas can also reveal differentiation into smooth muscle cells, fibroblasts, myofibroblasts, and chondroid cell differentiation indicating its pluripotent cell of origin. In the present case, pathological examination of right atrial myxoma was little unusual on both gross and microscopic findings. Grossly, it was globular and firm to little hard in consistency than the usual myxomas and on microscopically, the tumor was more cellular with predominant trabecular pattern with few single cells and Vasoformative pattern. The extracellular myxoid matrix was less and shows tiny cystic vacuoles surrounding the cell clusters. CD 31 immunostain highlighted the vessels. Lepidic cells were immunopositive for Calretenin [Figure 1]. However, the proliferative index of the tumor (KI 67 labeling index) was low. Mitotic figures were not identified. In our experience of more than 500 myxomas at our center, we never encountered myxoma with this much of cellularity. Hence, we are labeling it as “cellular cardiac myxoma” as a rare histopathological subtype. This entity is like that of any other cellular mesenchymal tumors like cellular schwannoma, cellular leiomyoma, etc. This entity is just a new histopathological subtype and it will not alter the treatment protocol or patient prognosis.[7],[8]

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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