|Year : 2015 | Volume
| Issue : 1 | Page : 111-113
Placental site nodule: A tumor like trophoblastic lesion - rare case report
Assistant Professor, Department of Pathology, Prathima Institute of Medical Sciences, Karimnagar. Andhra Pradesh, India
|Date of Web Publication||8-Jan-2015|
Assistant Professor, Department of Pathology, Prathima Institute of Medical Sciences, Karimnagar, Andhra Pradesh
Source of Support: None, Conflict of Interest: None
Placental site nodule (PSN) is an uncommon, benign, generally asymptomatic lesion of trophoblastic origin, which may often be detected several months to years after the pregnancy from which it is resulted. This entity may have bizarre histologic findings and should be distinguished from other aggressive lesions like placental site trophoblastic tumor, epithelioid trophoblastic tumor and squamous cell carcinoma.
Keywords: Gestational trophoblastic diseases, intermediate trophoblast, trophoblast
|How to cite this article:|
Shastry S. Placental site nodule: A tumor like trophoblastic lesion - rare case report. Med J DY Patil Univ 2015;8:111-3
| Introduction|| |
Placental site nodule is a rare, benign lesion which represents remnants of intermediate trophoblast from a previous gestation that has failed to completely involute , Although PSN occurs in the reproductive age group, a temporal association with recent pregnancy is usually lacking and often the time interval between pregnancy and diagnosis of PSN can be several years. These lesions are discovered as incidental findings in curettage or hysterectomy specimens performed for evaluation of irregular uterine bleeding, abnormal cervical smears, post coital bleeding etc. ,, Infertility is a rare mode of presentation in PSN. PSN needs to be differentiated from aggressive lesions of intermediate trophoblast like placental site trophoblastic tumor and epithelioid trophoblastic tumor and from nontrophoblastic diseases like squamous cell carcinoma. , Here we present a case of PSN in a 34-year-old women.
| Case Report|| |
A 34-year-old female presented with complaints of abnormal uterine bleeding and pain abdomen from past 3 months. She had a full term normal vaginal delivery 3 years ago. Her menstrual history was unremarkable. There was no history of abortions or irregular bleeding per vaginum since then. General physical examination and routine gynecologic check up were normal. Serum prolactin and progesterone levels were within normal limits. USG suggested bulky uterus with adenomyosis. Total abdominal hysterectomy was done and we received already cut opened uterus with bilateral adneaxae. Uterus measuring 7 × 4 × 3 cm 3 . Both ovaries appear normal, both tubes show fimbrialcysts. (l.) Endometrial cavity was obliterated, myometrium was 4 cm showing multiple well defined dark brown colored lesions of size 0.3 cm [Figure 1]. Sections were taken from the brownish lesions and under microscopy show small cells with clear cytoplasm and indistinct outlines in groups, cords [Figure 2] and also large cells with pleomorphic, hyperchromatic bizarre nuclei and abundant eosinophilic cytoplasm. Round eosinophilic hyaline bodies were also seen [Figure 3]. No decidua or chorionic villi were present.
|Figure 1: Hysterectomy specimen with bilateral adnexae, myometriun showing multiple dark brown lesions. [Fig 1a and b]|
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|Figure 2: Section fromnodules showed extensive hyalinization, within which were seen cells with indistinct outlines placed in small groups, singly or in cords (HandE, ×40)|
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|Figure 3: Small and large cells with clear cytoplasm and indistinct outlines in groups and cordswithpleomorphic, hyperchromatic bizarre nuclei and abundant eosinophilic cytoplasm (H and E, ×40). Inset — round, eosinophilic hyaline bodies|
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| Discussion|| |
Placental site nodule is a rare benign trophoblastic lesion deriving from implantation type intermediate trophoblasts. 
Gestational trophoblastic disease constitutes a diverse group of lesions, which also includes neoplastic and non-neoplastic proliferations of trophoblast unaccompanied by chorionic villi. A spectrum of lesions derived from the intermediate trophoblast has been described, viz. placental site nodule or plaque, exaggerated placental site reaction, placental site trophoblastic tumor and epithelioid trophoblastic tumor.  Placental site nodule (PSN) represents remnants of placental site tissue that has failed to involute and may remain in the uterus for several years after the pregnancy from which it resulted. The interval from the most recent known pregnancy till the time of detection ranges widely from 1 month to 8 years with an average of 3 years.  The mean age at diagnosis is in the early 30s with the age range as broad as 20 to 49 years. , The clinical indications for surgical evaluation included metro-menorrhagia, hypermenorrhoea, dysmenorrhoea, recurrent abortions, post-coital bleeding, abnormal cervical smear, and infertility etc. ,
Although the overwhelming majority involves the endometrium, PSN can occasionally be seen in the cervix and rarely in the Fallopian tube and ovary.  PSN is generally of microscopic size but when evident grossly, it appears as yellowish or tan surface nodules in the endometrium. The size of the lesion varies from 1 to 14 mm with average of 2.1 mm. , Microscopically, PSN is characterized by single or multiple, small round or ovoid, well defined extensively hyalinized eosinophilic nodules composed of cords, clusters and single cells of intermediate trophoblast. The cells are small with glycogen rich clear cytoplasm or large with abundant eosinophilic to amphophilic cytoplasm. Nuclear hyperchromatism, multinucleation and degenerative atypia are common, but mitotic figures are rarely seen. , Small, round eosinophilic cytoplasmic inclusions and Mallory's hyaline have been described within the trophoblastic cells.  PSN is a benign lesion with no evidence of recurrence requiring no specific treatment or follow up. ,
The differential diagnosis of PSN includes other lesions of intermediate trophoblast like placental site trophoblastic tumor, epithelioid trophoblastic tumor and exaggerated placental site reaction. The small size, presence of well defined, poorly cellular hyaline nodules with paucity of mitotic figures and lack of association with current or recent pregnancy differentiate PSN from these trophoblastic lesions. PSNs are positive for placental alkaline phosphatase and negative/focally positive for Mel-CAM and hpL in contrast to placental site trophoblastic tumors.  Exaggerated placental site reaction is distinguished by an admixture of intermediate trophoblast and syncytiotrophoblastic cells laid out in cords and nests and by the absence of hyaline nodules. Placental site trophoblastic tumor differs from PSN by features of trophoblastic infiltration of muscle fibers and vasculotropism. Nontrophoblastic lesions that may be confused with PSN include squamous cell carcinoma. Larger size, greater cytological atypia with mitosis and the presence of keratinized cells are pointers toward squamous carcinoma. Additionally, immunoreactivity for inhibin alpha and cytokeratin 18 and a low Ki-67 labeling index favor PSN.  PSN has also often been misinterpreted as hyalinized decidua. Decidual cells have more distinct cell membranes, basophilic cytoplasm and pale, uniform nuclei in contrast to the amphophilic or deeply eosinophilic cytoplasm and hyperchromatic, often pleomorphic nuclei of PSN. Intermediate trophoblastic cells are positive for both cytokeratin and hpL, while decidual cells are negative.
Although it is a benign lesion, because of its histomorphological appearance, its differential diagnosis is important from placental site trophoblastic and epithelioid trophoblastic tumors which are aggressive lesions of intermediate trophoblasts as well as non-trophoblastic neoplasm like squamous cell carcinoma. ,
To conclude, PSN may have bizarre histologic features necessitating differentiation from aggressive lesions of intermediate trophoblast and from squamous carcinoma. The lack of association with recent pregnancy compounds the problem. Herein lies the importance of this, infrequently encountered, less known benign trophoblastic lesion. We present this case because of its rarity and importance of myometrial nodules which may miss on grossing.
| References|| |
Young RH, Kurman RJ, Scully RE. Placental site nodules and plaques: A clinicopathologic analysis of 20 cases. Am J Surg Pathol 1990;4:1001-9.
Huettner PC, Gersell DJ. Placental site nodule: A clinicopathologic study of 38 cases. Int J Gynecol Pathol 1994;13:191-8.
Shih IM, Seidman JD, Kurman RJ. Placental site nodule and characterization of distinctive types of intermediate trophoblast. Hum Pathol 1999;30:687-94.
Shih IM, Kurman RJ. The pathology of intermediate trophoblastic tumors and tumor-like lesions. Int J Gynecol Pathol 2001;20:31-47.
Jacob S, Mohapatra D. Placental site nodule: a tumor-like trophoblastic lesion. Indian J Pathol Microbiol 2009; 52: 240-1.
O'Neill CJ, Cook I, Mc Cluggage WG. Postcesarean delivery uterine diffuse intermediate trophoblastic lesion resembling placental site plaque. Hum Pathol 2009;40:1358-60.
Stolnicu S, Radulescu D, González-Rocha T, Timar I, Puscasiu L, Nogales FF. Exaggerated placental site lesion with unusual presentation in the cervix of a perimenopausal patient. APMIS 2008;116:160-2.
[Figure 1], [Figure 2], [Figure 3]