BOTs are APOTs.

Given the confusion that I already have, imagine my delight at discovering yet another acronym:  APOT.  Apparently, this is an Atypical Proliferative Ovarian Tumour; otherwise known as BOT (so, they’re the same thing).

At least the piece where I discovered APOTs clearly indicates exactly what my consultant emphasised: At the present time, the use of the designation “low malignant potential” is not recommended. 

Good.

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Taken from:  

Borderline Ovarian Tumors – Atypical Proliferative Ovarian Tumors

Amortegui, A, Trucco, G, et al, Glob. libr. women’s med.,
(ISSN: 1756-2228) 2013; DOI 10.3843/GLOWM.10247

The borderline ovarian tumors (BOTs) or atypical proliferative ovarian tumors (APOTs) are of particular importance to the women affected and to gynecologists caring for them as well as to the women’s families. They are also important for the pathologists charged with establishing an accurate diagnosis and for the researchers who are trying to explain the tumors’ complex pathogenesis.

BOTs or APOTs are of epithelial origin and represent a unique intermediate stage between the benign cystadenomas and the adenocarcinomas. They are separated from cystadenomas by the presence of cellular atypia and from high-grade malignant tumors by the presence of destructive stromal invasion. Some BOTs or APOTs have a minor form of invasion designated as microinvasion; some tumors present small focal areas that exhibit moderate to severe atypia that are designated as intraepithelial carcinomas. BOTs or APOTs share multiple similarities and differences as demonstrated below.^1, 2

BOTs or APOTs represent 15–20% of atypical cell proliferations of the ovary.^3, 4, 5 In general, these tumors have an excellent disease-free survival after surgical treatment. BOTs or APOTs have been recognized for more than 70 years; nevertheless, several authors going back to the late 1800s reported ovarian tumors with histological and clinical features between benign cystadenoma and high-grade malignant tumors.^6, 7, 8 The BOTs or APOTs were separated into a new category of neoplastic processes as a result of the observation made by Taylor and others^9, 10, 11 who noted that some tumors displaying papillary features and some with tumor deposits on the peritoneal surface had excellent survival, especially those of serous type. However, other tumors with the same stage and somewhat similar histologic architecture were rapidly fatal. The serous cystadenoma can progress to BOTs or APOTs and finally becomes a serous low-grade carcinoma. These three entities (cystadenoma, BOT or APOT, and low-grade serous carcinoma) are different biologically, in their clinical course and treatment modalities.^{1, 2, 11, 12, 13, 14}

In 1971 the Cancer Committee of the International Federation of Gynecology and Obstetrics^15, 16, proposed a classification of common primary epithelial ovarian tumors. They subdivided the tumors into benign cystadenoma, cystadenoma with proliferative activity of the epithelial cells and nuclear abnormalities, but with no infiltrative destructive growth, low malignant potential tumors, and cystadenocarcinoma. Later in 1973, the World Health Organization¹² catalogued tumors with histologic characteristics of carcinoma, but with good behavior as “tumors of borderline malignancy”.

In the WHO classification of 2003,¹⁵ these neoplasms are simply designated as “borderline tumors”; they have been too widely recognized as ovarian tumors of “low malignant potential,” and as “proliferative ovarian tumors,“ terminology that was accepted by the WHO in the year 2000.¹⁷ At the present time, the use of the designation “low malignant potential” is not recommended.