Departments of *Pathology ‡Oncology §Urology, The Johns Hopkins Medical Institutions, Baltimore, MD †Institute of Pathology, St Luke's Medical Center, Quezon City, Philippines.
Am J Surg Pathol. 2014 Jun;38(6):852-7. doi: 10.1097/PAS.0000000000000193.
Perineural invasion (PNI) seen in prostatic adenocarcinoma (PCa) on biopsy has both diagnostic and prognostic implications. On biopsy, PNI is 1 of the 4 pathognomonic features of PCa; it is associated with an increased risk for extraprostatic extension, and its finding can affect therapy. From January 1, 2013 to June 30, 2013, 3120 cases of PCa were seen by the Genitourinary Pathology Consultation Service at the Johns Hopkins Hospital. Of these, 418 (13.4%) had PNI. During this interval, we prospectively identified an unusual pattern of PNI, which we have termed "pseudohyperplastic PNI," which was defined by a "gland-within-gland" morphology, wherein the centrally located gland was wrapped around a nerve. Pseudohyperplastic PNI was found in 9 (2.1%) cases, with an additional 3 cores from 2 patients biopsied at our institution with this finding also included. Of the 12 cores with pseudohyperplastic PNI, the Gleason scores were 6 in 11 cores and 4+3=7 in the remaining core. In 6 cases, the only focus of PNI in the entire case was pseudohyperplastic. In 7 of the 12 foci, the central gland wrapping around the nerve appeared to "float" unattached within the surrounding gland closely resembling a benign hyperplastic gland or high-grade prostatic intraepithelial neoplasia (HGPIN). In the remaining 5 foci, the central PNI was focally attached to the outer gland. In 11 of 12 foci, there was no to mild cytologic atypia. One focus of pseudohyperplastic PNI had prominent nucleoli in a large gland with tufting architecture and foamy cytoplasm. Of the 9 consult cases, pseudohyperplastic PNI was missed in 5, and in all 5 cases PNI was initially not diagnosed in the entire case. In 2 of these cases with missed pseudohyperplastic PNI, PCa was not diagnosed at the outside institution. In 1 of the cases biopsied at our institution, pseudohyperplastic PNI was misdiagnosed as HGPIN. In addition to the morphology of cancer appearing to float within a surrounding gland, other features that contribute to the difficulty of recognizing the focus as cancer are: (1) lack of adjacent cancer in about one half of the foci; (2) larger glands than typical cancer surrounding the PNI in a minority of cases; (3) tufting of the gland surrounding the PNI in a few cases; (4) atrophic or foamy gland features in some cases; and (5) lack of prominent cytologic atypia in most cases. Although this pattern of PNI that mimics either a benign hyperplastic gland or HGPIN is uncommon, accurately recognizing it as carcinoma can have both diagnostic and prognostic implications.
前列腺腺癌（PCa）活检中观察到的神经周围侵犯（PNI）具有诊断和预后意义。在活检中，PNI 是 PCa 的 4 个特征性表现之一；它与前列腺外延伸的风险增加有关，其发现可以影响治疗。2013 年 1 月 1 日至 6 月 30 日，约翰霍普金斯医院的泌尿生殖系统病理学咨询服务共诊断 3120 例 PCa，其中 418 例（13.4%）存在 PNI。在此期间，我们前瞻性地确定了一种不常见的 PNI 模式，我们将其称为“假增生性 PNI”，其特征为“腺体内包腺”形态，其中中央腺被包裹在神经周围。9 例（2.1%）发现假增生性 PNI，另外还有 3 例来自我们机构的活检也发现了这种表现。在 12 个具有假增生性 PNI 的核心中，11 个核心的 Gleason 评分为 6，其余 1 个核心为 4+3=7。在 6 例中，整个病例中唯一的 PNI 焦点是假增生性。在 12 个焦点中的 7 个中，包裹在神经周围的中央腺似乎“漂浮”而未附着在周围的腺体内，与良性增生腺或高级别前列腺上皮内瘤变（HGPIN）非常相似。在其余 5 个焦点中，中央 PNI 局部附着于外腺。在 11 个焦点中，细胞异型性无到轻度。一个假增生性 PNI 焦点的大腺体内有明显的核仁，呈簇状结构，泡沫状细胞质。在 9 例会诊病例中，5 例漏诊假增生性 PNI，在所有 5 例中，整个病例最初都未诊断出 PNI。在这 5 例漏诊假增生性 PNI 的病例中，有 2 例在外部机构未诊断出 PCa。在我们机构活检的 1 例病例中，假增生性 PNI 误诊为 HGPIN。除了癌症形态似乎在周围腺体中漂浮之外，还有其他特征也会导致难以识别该焦点为癌症：（1）大约一半的焦点缺乏相邻的癌症；（2）在少数情况下，周围 PNI 的腺体比典型的癌症大；（3）少数情况下 PNI 周围的腺体簇状；（4）一些病例腺体内萎缩或泡沫状；（5）大多数病例缺乏明显的细胞异型性。虽然这种模仿良性增生腺或 HGPIN 的 PNI 模式并不常见，但准确识别为癌具有诊断和预后意义。
