Anatomic aspects of inguinal lymph nodes applied to lymphadenectomy in penile cancer

Abstract

Objectives. To provide a better understanding of the distribution of inguinal nodes in order to prevent the complications of unnecessary and extended dissections in penile cancer. Methods. The bilateral inguinal regions of 19 male cadavers were dissected. Nodal distribution was noted and quantified based on anatomical location. The superficial nodes were subdivided into quarters as follows: superomedial, superolateral, inferomedial, and inferolateral. Statistical analysis was performed comparing node distribution between quarters using one-way analysis of variance (ANOVA), and the unpaired T-test was used between superficial and deep nodes. Results. Superficial nodes were found in all inguinal regions studied (mean = 13.60), and their distribution was more prominent in the superomedial quarter (mean = 3.94) and less in the inferolateral quarter (mean = 2.73). There was statistical significance between quarters when comparing the upper group with the lower one (P = 0.02). Nodes were widely distributed in the superficial region compared with deep lymph nodes (mean = 13.60 versus 1.71, P < 0.001). Conclusions. A great number of inguinal lymph nodes are distributed near the classical anatomical landmarks for inguinal lymphadenectomy, more prominent in upper quadrants.

Figure 1

Schematic drawing of lymphatic drainage of inguinal nodes. There is a cross with its middle point in the saphena hiatus. The penile and scrotum lymphatic drainage is performed, by the upper internal quarter (arrows).

Figure 2

(a) Inguino crural dissection in a formalin-preserved cadaver. The subcutaneous tissue has been removed and the following structures can be identified: (1) saphena magna vein; (2) superficial lymph nodes; (3) superficial epigastric vein; (4) accessory saphena vein; (5) *-external pudendal vein. (b) Schematic draw of the superficial inguinal region and nodes.

Figure 3

(a) Inguino crural dissection in formalin-preserved cadaver. The superficial nodes (SN) remain in their original position. In this specimen, just one deep inguinal lymph node is located medially to the femoral vein (F). S: saphena magna vein; SE: superficial epigastric vein; *-external pudendal vein; SSN: superficial sentinel node, as previously described by Cabanas [10, 11]. (b) Schematic draw with superficial and deep nodes of the inguinal region and the iliac nodes.

Figure 4

Average superficial nodes distribution versus quarters; SL: superolateral; SM: superomedial; IL: inferolateral; IM: inferomedial quarters. No statistically difference between samples.