Urology Unit, Department of Surgery Dermatology Unit, Department of Medicine, University College Hospital, Ibadan, Nigeria.
Int J Dermatol. 2012 Nov;51 Suppl 1:41-3, 45-8. doi: 10.1111/j.1365-4632.2012.05564.x.
Linea nigra (LN) is linear hyperpigmentation occurring from the umbilicus to the pubic symphysis. Although commonly associated with pregnancy (when it is known as linea gravidarum), it has been found in normal male and female individuals, particularly in the younger age group where estrogen or lack of sensitivity of androgen receptors has been suggested as a possible factor. From a previous study the incidence of LN varied in different genders, age groups, and certain clinical status such as pregnancy and, in men, benign prostate hyperplasia (BPH)/prostate carcinoma (PC).
The need to get a clinical feature that can aid diagnosis of PC, the commonest male neoplasm in Nigeria, at an affordable cost prompted us to look at the incidence of LN in three male populations (i.e., one with BPH, one with PC, and a control population unaffected by these two conditions). Gynecomastia and female hair distribution, two features considered hormone related were looked for additionally in the study population. The study was carried out in a teaching hospital in Ibadan, southwestern Nigeria.
LN was found in 48% of PC, 26% of BPH, and 8% of controls. Female pubic hair was found in 48% of PC, 26% of BPH, and 12% of controls. Gynecomastia was found in 36% of PC, 12% of BPH, and 0% of controls. Differences between patients with BPH, PC, and controls regarding incidence of LN and female pubic hair were deemed explicable by chance (P = 0.17, Fisher exact test). Differences between PC and BPH patients with respect to gynecomastia were deemed inexplicable by chance (P = 0.008, Fisher exact test).
LN alone cannot be used to differentiate PC and BPH. Further studies will be needed to characterize the role of LN in these conditions in men before and after treatment.
黑线（LN）是从脐部延伸到耻骨联合的线性色素沉着。虽然它通常与妊娠有关（此时称为妊娠线），但也存在于正常的男性和女性个体中，尤其是在年轻人群中，雌激素或雄激素受体不敏感被认为是一个可能的因素。从之前的研究中可以看出，LN 的发病率在不同的性别、年龄组和某些临床状况（如妊娠）中有所不同，在男性中，还与良性前列腺增生（BPH）/前列腺癌（PC）有关。
为了在负担得起的成本下获得有助于诊断在尼日利亚最常见的男性肿瘤 PC 的临床特征，我们观察了三种男性人群（即患有 BPH、患有 PC 和未受这两种疾病影响的对照组）中 LN 的发病率。此外，还研究了研究人群中的两种被认为与激素有关的特征：男性乳房发育和女性阴毛分布。该研究在尼日利亚西南部伊巴丹的一家教学医院进行。
在 PC 中，48%的患者存在 LN，26%的患者存在 BPH，8%的对照组存在 LN。在 PC 中，48%的患者存在女性阴毛，26%的患者存在 BPH，12%的对照组存在女性阴毛。在 PC 中，36%的患者存在男性乳房发育，12%的患者存在 BPH，0%的对照组存在男性乳房发育。BPH、PC 和对照组患者之间关于 LN 和女性阴毛发病率的差异被认为是偶然的（P = 0.17，Fisher 精确检验）。PC 和 BPH 患者之间关于男性乳房发育的差异被认为是偶然的（P = 0.008，Fisher 精确检验）。
LN 本身不能用于区分 PC 和 BPH。在治疗前后，还需要进一步研究 LN 在这些男性疾病中的作用。
