Ovarian Microcystic Stromal Tumor: Report of A New Entity with Immunohistochemical and Ultrastructural Studies

Microcystic stromal tumour of testis

Within the group of gonadal sex cord-stromal tumours, microcystic stromal tumour (MCST) is a rare entity. In the literature, most case series and reviews discussed MCST arising in the ovary, only one case-report concerned a testicular MCST. We present a Caucasian man in his late 30s, who presented with an MCST in his right testis. The tumour was encapsulated and composed of vaguely lobulated cellular nodules and cystic spaces with bland spindle cells and hyalinised fibrous stroma. By immunohistochemistry, the tumour cells expressed cluster designation 10, androgen receptor, steroidogenic factor-1 and nuclear beta-catenine, and there was focal nuclear expression of cyclin D1. Molecular diagnostics confirmed the presence of an exon 3 mutation (c.98C>T) in the CTNNB1 gene. These features are similar to MSCT described in the ovary. Clinical follow-up (more than 1 year) was uneventful.Although the clinical and radiological presentation was that of a possible malignant testicular lesion, this entity is benign.

A 46-Year-Old Woman with Primary Infertility and a Diagnosis of Microcystic Stromal Tumor of the Ovary Confirmed by Histology and Gene Sequencing: A Case Report and Review of the Literature

Patient: Female, 46-year-old

Final Diagnosis: Microcystic stromal tumor of the ovary

Symptoms: Abdominal pain • vaginal bleeding

Medication: —

Clinical Procedure: —

Specialty: Pathology

Ovarian microcystic stromal tumor with omental metastasis: the first case report and literature review

Background

Microcystic stromal tumor (MCST) of the ovary is an extremely rare subtype of sex cord-stromal neoplasm first described by Irving and Young in 2009. Tumors from all previously reported cases (fewer than 40 total) were benign, but one was a case of ovarian MCST that reoccurred.

Case presentation

Herein, we present a unique single case of ovarian MCST with omental metastasis in a 47-year-old Chinese female along with its histologic and immunohistochemical profile and genetic alterations. The tumor exhibited the previously described classic microscopic features and immunoprofiles of MCST. The tumorlet in the omentum presented the same histological structures and characteristically expressed β-catenin protein (localized in the nucleus). Molecular analysis identified a point mutation (c.98C > G) in exon 3 of CTNNB1.

Conclusions

To the best of our knowledge, no such report has been documented for ovarian MCST with omental metastasis. The study may provide new insights into the tumor biology of MCST and provide a better understanding of this rare entity.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13048-021-00812-1.

Ovarian Microcystic Stromal Tumor: A Case Report and Literature Review

Background: Microcystic stromal tumor is a recently described subtype of ovarian tumor characterized by microcystic pattern and diffuse immunoreactivity for CD10, vimentin, and β-catenin and negative for EMA. However, its diagnostic criterion and standard treatment remain unclear. Case presentation: We report a rare case of a left side microcystic stromal tumor with diameter about 7 cm in a 25-year-old female and summarize all cases of MCST reported in this study. The present patient underwent left ovarian tumor resection. Generally, the tumor was solid and cystic mixed. Immunohistochemically, the tumor was expressed CD10, WT1, cyclin D1 and vimentin, and nuclear immunoreactivity for β-catenin but negative for α-inhibin, calretinin, CK AE1/AE3, PLAP, SALL-4, CK7, P53, EMA, CD99, AFP, desmin, CgA, E-cadherin, and melanA. Conclusion: Unilateral ovary, solid-cystic, and a larger than 4-8 cm pelvic mass without serious abdominal pain are its clinical features. The immunophenotype of vimentin+/CD10+/WT-1+/β-catenin+(nuclei)/cyclin D1+ is supportive of diagnosis. For these patients, unilateral oophorectomy dissection could be selected.

Ovarian microcystic stromal tumor: Radiologic-pathologic correlation

Ovarian microcystic stromal tumor (MST) is characterized by microcysts, solid cellular regions with lobulated growth, and collagenous or fibrous stroma forming hyaline plaques. While several reports have evaluated the unique pathologic and immunohistochemical profile of these tumors, there has been limited description of the radiologic findings of ovarian microcystic stromal tumor in the literature. We present a case of a 66 year old female who presented for evaluation of a new cystic pelvic mass found to have ovarian microcystic stromal tumor. To our knowledge, this is one of the first reports to evaluate the radiologic features associated with this tumor. An enhanced understanding of the correlation between imaging appearance and specific histopathologic findings may aid in the early recognition of this rare neoplasm.

Microcystic Stromal Tumor of Testicle: First Case Report and Literature Review

Microcystic stromal tumor (MCST) is a rare subtype of sex cord-stromal neoplasm. Tumors from all 31 previously reported cases were located in the ovary. Herein, we present a unique case of a right-side testicular tumor in a 33-year-old Chinese male. The tumor is composed of predominantly lobulated cellular nodules separated by hyalinized fibrous stroma and they expressed CD10, β-catenin (nuclear), and cyclin D1. Molecular analysis identified a point mutation (c.110C>G) in exon 3 of CTNNB1. The histopathological features, immunohistochemistry profiles, and molecular analysis of this tumor were consistent with MCST of the ovary. Therefore, a diagnosis of MCST of the right testicle was determined. To the best of our knowledge, this is the first case of MCST occurring in the testicles. The study may provide new insights to the tumor biology of MCST and a better understanding of this rare entity.

Genetic analysis of ovarian microcystic stromal tumor

Microcystic stromal tumor (MCST) of the ovary is a rare subtype of ovarian tumor first described in 2009. Although high nuclear expression of β-catenin and β-catenin gene (CTNNB1) mutation are related with ovarian MCST, the origin and genetic background of ovarian MCST remain unclear. In this study, two cases of ovarian MCST are presented. Microscopically, the tumors showed a microcystic pattern and regions with lobulated cellular masses with intervening hyalinized, fibrous stroma. Tumor cells of both cases were stained with CD10, vimentin, and Wilms tumor 1. Genetic analysis was performed and β-catenin gene (CTNNB1) mutation in exon 3 was detected in both cases. This is the first report in regards of detecting CTNNB1 mutation in ovarian MCST through the use of pyrosequencing (a novel sequencing technique).

Microcystic stromal tumour of the ovary: frequent mutations of β-catenin (CTNNB1) in six cases

AIMS

To analyse the clinicopathological, immunohistochemical and β-catenin (CTNNB1) mutation characteristics of six cases of microcystic stromal tumour of the ovary (MCST).

METHODS AND RESULTS

Six Chinese patients with MCST who ranged in age from 29 to 69 years (mean 50 years) were included in the study. Five patients were detected with a pelvic mass during routine health examinations and one patient presented initially with opsomenorrhoea. All tumours involved the left ovary, with solid-cystic cut surface in five cases and cystic cut surface in one case. Microscopically, microcysts, solid nests and hyaline degenerated fibrous stroma were variably mixed. Immunohistochemically, the tumour cells in all cases were diffusely positive for CD10, vimentin and WT-1 and negative for α-inhibin and calretinin. β-catenin expression was observed in both the nucleus and the cytoplasm in five cases and only in the cytoplasm in one case. The results of CTNNB1 mutation analysis revealed four missense point mutations in four cases, which were c.97T>C, c.101G>A, c.110C>G and c.122C>T.

CONCLUSIONS

MCST shows a unique morphology with characteristic immunophenotype. β-catenin expression in the nucleus and β-catenin mutations were identified in the majority of cases, which suggests that the Wnt/β-catenin pathway may play a crucial role in the tumorigenesis of MCST.