Cheville J C, Bostwick D G
Department of Pathology, Mayo Clinic, Rochester, MN 55905, USA.
Am J Surg Pathol. 1995 Sep;19(9):1068-76. doi: 10.1097/00000478-199509000-00011.
Clusters of atrophic prostatic acini that display proliferative epithelial changes are referred to as postatrophic hyperplasia (PAH). PAH is histologically similar to adenocarcinoma and may cause diagnostic confusion. Despite the importance of distinguishing PAH from carcinoma, the last systematic study of this lesion was reported > 40 years ago, and many contemporary pathologists are unfamiliar with this lesion. We reviewed 100 consecutive whole-mount radical prostatectomy specimens removed for carcinoma to determine the incidence of PAH. In addition, 11 prostatic needle biopsy specimens with PAH were evaluated to further characterize the lesion in limited specimens. PAH was identified in 18 radical prostatectomies (18%), including 10 unicentric and eight multicentric cases. It was found exclusively in the peripheral zone in all but two cases, which had additional involvement of the transition zone. PAH consisted of a microscopic lobular cluster of small acini with irregular atrophic-appearing contours lined by cuboidal cells with mild nucleomegaly and micronucleoli; mildly enlarged nucleoli were focally present in 39% of cases. Within the small acinar cluster, a larger dilated acinus was usually present centrally, which was lined by flattened to cuboidal epithelial cells. The basal cell layer at the periphery of each acinus was invariably present but often inconspicuous. Immunohistochemical staining for high-molecular-weight keratin (antibody 34 beta E12) showed the presence of an intact basal cell layer in seven of 10 cases and a focally fragmented basal cell layer in three other cases. PAH was associated with patchy chronic inflammation in 16 of 18 prostatectomy cases; stromal changes were present in all cases, ranging from smooth atrophy to dense sclerosis with compression of acini. No intraluminal basophilic mucin was identified, but two needle biopsies showed PAH with focal mucinous metaplasia. Crystalloids were not seen in any case. Focal partial acinar involvement by high-grade prostatic intraepithelial neoplasia was present in adjacent acini in two cases. Adjacent acini also invariably showed typical changes of atrophy. In the needle biopsy specimens, PAH showed the same features as those in prostatectomies, but often only a portion of the lesion was sampled. PAH is distinguished from carcinoma by its characteristic architecture, intact or fragmented basal cell layer, inconspicuous or mildly enlarged nucleoli, and adjacent acinar atrophy with stromal fibrosis or smooth muscle atrophy. Distinguishing PAH from carcinoma is most difficult in needle biopsy specimens in which only a portion of the lesion is sampled, and awareness of this entity assists in this distinction.
呈现增殖性上皮改变的萎缩性前列腺腺泡簇被称为萎缩后增生（PAH）。PAH在组织学上与腺癌相似，可能导致诊断混淆。尽管区分PAH与癌很重要，但对该病变的最后一项系统性研究是在40多年前报道的，许多当代病理学家并不熟悉这种病变。我们回顾了100例因癌切除的连续前列腺根治性切除标本，以确定PAH的发生率。此外，对11例有PAH的前列腺穿刺活检标本进行评估，以进一步在有限标本中对该病变进行特征描述。在18例前列腺根治性切除标本中发现了PAH（18%），包括10例单中心和8例多中心病例。除2例病变累及移行区外，其余均仅见于外周区。PAH由微小腺泡小叶簇组成，腺泡轮廓不规则，呈萎缩状，内衬立方体细胞，细胞核轻度增大，可见微核仁；39%的病例细胞核仁有局灶性轻度增大。在小腺泡簇内，通常在中央有一个较大的扩张腺泡，内衬扁平至立方上皮细胞。每个腺泡外周的基底细胞层始终存在，但通常不明显。高分子量角蛋白（抗体34βE12）免疫组化染色显示，10例中有7例基底细胞层完整，另外3例基底细胞层有局灶性断裂。18例前列腺切除病例中有16例PAH伴有散在性慢性炎症；所有病例均有间质改变，从平滑萎缩到致密硬化伴腺泡受压。未发现管腔内嗜碱性黏液，但2例穿刺活检显示PAH伴有局灶性黏液化生。所有病例均未见到结晶体。2例相邻腺泡有高级别前列腺上皮内瘤变的局灶性部分腺泡受累。相邻腺泡也总是呈现典型的萎缩改变。在穿刺活检标本中，PAH表现出与前列腺切除标本相同的特征，但通常仅取到病变的一部分。PAH通过其特征性结构、完整或断裂的基底细胞层、不明显或轻度增大的核仁以及相邻腺泡萎缩伴间质纤维化或平滑肌萎缩与癌相鉴别。在仅取到病变一部分的穿刺活检标本中，区分PAH与癌最为困难，认识到这种实体有助于进行鉴别。
