Journal of Dr. NTR University of Health Sciences

CASE REPORT
Year
: 2021  |  Volume : 10  |  Issue : 3  |  Page : 200--204

Histological conversion of seminoma of testis to metastatic choriocarcinoma in left cervical lymph node: An unusual phenomenon


Shirin Dasgupta, Debahuti Mohapatra 
 Department of Pathology, IMS and SUM Hospital, Bhubaneswar, Odisha, India

Correspondence Address:
Dr. Shirin Dasgupta
Quarter number: NFA-67, IIT Campus, Kharagpur - 721 302, West Bengal
India

Abstract

Germ cell tumors (GCT) of more than one histological subtype (although very rare) can be present in the same patient. We present a 29-year-old male who presented with a cervical lymph node swelling. The tissue received was a globular mass with a thick cystic wall and necrotic areas. A histopathological examination revealed the presence of residual lymphoid tissue in the form of lymphoid follicles, areas of hemorrhage and necrosis, tumor nests, and perivascular distribution of tumor cells. The neoplastic cells were arranged in a vague glandular pattern and also showed squamoid-like morphology on the basis of which a diagnosis of metastatic adenosquamous carcinoma was made. The patient was subjected to a whole-body positron emission tomography (PET) scan to look for primary on which a testicular mass was discovered; seminoma on histology. The sections of the cervical mass were revisited and trophoblastic cells were identified; they were also positive for β- human chorionic gonadotropin (hCG) on Immunohistochemistry. Therefore, a diagnosis of metastatic choriocarcinoma from seminoma testis was made. The direct derivative of germ cell neoplasia in situ/intratubular germ cell neoplasia being seminoma; it has the capacity for histological conversion to more differentiated forms (choriocarcinoma in this case).



How to cite this article:
Dasgupta S, Mohapatra D. Histological conversion of seminoma of testis to metastatic choriocarcinoma in left cervical lymph node: An unusual phenomenon.J NTR Univ Health Sci 2021;10:200-204


How to cite this URL:
Dasgupta S, Mohapatra D. Histological conversion of seminoma of testis to metastatic choriocarcinoma in left cervical lymph node: An unusual phenomenon. J NTR Univ Health Sci [serial online] 2021 [cited 2023 Feb 4 ];10:200-204
Available from: https://www.jdrntruhs.org/text.asp?2021/10/3/200/339803


Full Text



 Introduction



The contemporary presence of multiple germ cell tumors (GCT) of different histological subtypes, although rare, may be present in the same patient either as metastasis in the form of histological conversion of the less differentiated to the more differentiated form or the simultaneous occurrence of two different tumors of different histology (which seems the less possible phenomenon).[1] We present a case where there was a histological conversion of one germ cell tumor into a more differentiated form.

 Case Report



A 29-year-old male presented with hard well-circumscribed swelling on the left side of the neck which was somewhat rapidly growing. Excision of the mass was done and biopsy was sent. Grossly, the tissue looked globular and the cut surface showed a thick-walled cyst which had areas of hemorrhage and a necrotic center [Figure 1]a and [Figure 1]b. Histopathological sections showed residual lymphoid tissue in the form of lymphoid follicles, areas of hemorrhage and necrosis, tumor nests, and perivascular distribution of tumor cells [Figure 2]. The neoplastic cells were arranged in sheets nests and vague glandular pattern (some showed Periodic acid–Schiff (PAS_ positivity), showing significant pleomorphism having centrally placed nucleus, prominent nucleolus, moderate cytoplasm, somewhat ill-defined margins with areas of hemorrhage, and necrosis [Figure 3], [Figure 4], [Figure 5]. Considering the morphology, we thought of an epithelial malignancy and we did a panCK and p63 immunohistochemistry both of which came out to be positive. The panCK showed cytoplasmic positivity while p63 showed nuclear positivity. HMB45 was negative ruling out melanoma. So, we gave a diagnosis of metastatic adenosquamous carcinomatous deposits and suggested looking for the primary tumor.{Figure 1}{Figure 2}{Figure 3}{Figure 4}{Figure 5}

The patient was subjected to a PET scan of the whole body and a testicular mass was discovered. The orchidectomy was sent for histopathological study which revealed a well-demarcated, lobulated homogenous gray-white tumor tissue measuring 4.5 cm in greatest dimension [Figure 6]. No necrosis, hemorrhage, or invasion in the tunica albuginea were noted. Microscopy showed seminiferous tubules and a tumor tissue composed of lobules of neoplastic cells separated by fibrovascular connective tissue infiltrated with lymphocytes [Figure 7]. The tumor cells were round to polygonal having a central nucleus, clear cytoplasm, and distinct cell border [Figure 8]. Immunohistochemistry (IHC) with CD117 showed cytoplasmic positivity [Figure 9] and a diagnosis of seminoma was rendered. We decided to revisit the neck mass and reconsider our diagnosis of metastatic carcinoma and conduct a further extended panel of markers since there was a possibility of a metastatic/concurrent germ cell tumor. IHC with CD117 and CD30 came out to be negative ruling out metastatic seminoma and embryonal carcinoma. However, an IHC of tissue β-hCG came out to be diffusely cytoplasmic positive [Figure 10]. Also, on extensive examination of the histology slides, we did see some giant cells which earlier were thought to be tumor giant cells but now represented syncytiotrophoblast [Figure 4] and [Figure 5].{Figure 6}{Figure 7}{Figure 8}{Figure 9}{Figure 10}

A retrospective evaluation was done and it was found out that a pre-orchidectomy investigation of serum β-hCG was done, the value being 18 mIU/mL.

So, we gave a final conclusion of testicular seminoma which had undergone histological conversion to metastatic choriocarcinoma in the left cervical lymph node.

 Discussion



About 93% of all testicular neoplasms comprise of GCT; a good number of them being post-pubertal.[1] Seminomas comprise almost 50% of GCT and they can be subdivided into pure seminomas and seminomas mixed with some other germ cell components; in either case, the prognosis of seminomas is usually good.[2] Theory supports that all GCTs have a common origin from the embryonic cell; that is pluripotent germ cell. This pluripotent germ cell has the capacity to differentiate into various germ cell components, thus, mimicking the normal embryogenesis.[1]

Seminoma represents the neoplastic component of spermatocyte and is the most undifferentiated type. Choriocarcinomas (pure); the most differentiated form of GCT arises from the placental elements, syncytiotrophoblasts, and cytotrophoblasts.[3] They are the most differentiated yet malignant entities of the spectrum having the tendency for hematogenous metastasis and characteristically produce β-hCG in large amounts.

Simultaneous development of GCTs of two varied histological types in the same person is highly improbable. Instead, this finding in the same patient indicates the histological conversion of the less differentiated one to the more differentiated one.[3] This type of histological conversion in the form of metastasis of a less differentiated GCT to a more differentiated one has been studied in a few cases with germ cell tumors.[4] GCTs can metastasize only as more mature histological type (more differentiated type) in the way of embryogenesis and never in the reverse direction. Seminoma being the most undifferentiated tumor can theoretically convert to all the other subtypes (teratoma, yolk sac tumor, choriocarcinoma, and embryonal carcinoma) and choriocarcinoma being the most differentiated subtype can metastasize only as choriocarcinoma. But some authors believe that seminomas always retain their original morphology when they metastasize and do not covert randomly to another subtype. In cases where metastatic tumors present with different morphology, it is possible that the primary seminoma contained elements of the other GCTs which were missed initially.[1] Serum β-hCG levels are mild to moderately elevated in 10% of the patients with stage 1 seminoma and 25% with metastasis.[5]

Our patient presented with almost concurrent testicular seminoma and cervical choriocarcinoma. There is a theoretical possibility of the histological conversion of the primary undifferentiated seminoma into more differentiated choriocarcinoma. However, some authors may argue that there was a possibility that a concurrent choriocarcinomatous element might have been missed on the histopathological examination of the primary testicular mass which later on gave rise to metastasis. This can be partially contraindicated by the fact that the presence of syncytiotrophoblasts and cytotrophoblasts which are essential for choriocarcinoma diagnosis were absent; also, the testicular tumor was negative for IHC of tissue β-hCG. However, the pre-orchidectomy serum β-hCG was found above normal, but the β-hCG level before the excision of the neck mass was not done and hence could not be recorded. Also, the testicular mass was an almost incidental finding because the patient never complained of it and it was revealed only after a PET scan of the whole body after a diagnosis of suspicious metastasis of the cervical lymph node. A similar patient with testicular seminoma who initially presented with cervical lymphadenopathy was also presented.[6] It can hence be inferred that these GCTs have a tendency of presenting as mixed tumors (with other germ cell components; which may even overlap or be present in fewer amounts) and also have the capacity to differentiate in a more mature form in the form of metastasis; hence all clinicians (especially oncologists), as well as pathologists, must be extremely cautious about the initial histopathological diagnosis in these cases. Also, since these tumors are heterogenous one could highlight that it is essential to take sections from different areas of the tumor during grossing to reduce the possibility of missing any non-dominant element histologically which could, later on, change the diagnosis or therapy of the patient.[7]

 Conclusion



Histological conversion of a less differentiated subtype to a more differentiated subtype of germ cell tumor is theoretically possible as metastasis; which is unrelated to therapeutic intervention. More than one GCTs of different histology developing in the same patient is also possible since there might some instability in the developmental process of all GCTs originating from the common origin of pluripotent germ cell.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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