Haematopoietic bone marrow: An uncommon mesodermal derivative in mature teratoma

Tarak Banik; Krishnendu Mondal; Rupali Mandal

doi:10.4103/2468-6360.191914

CASE REPORT

Year : 2016 | Volume : 4 | Issue : 4 | Page : 297-300

Haematopoietic bone marrow: An uncommon mesodermal derivative in mature teratoma

Tarak Banik¹, Krishnendu Mondal¹, Rupali Mandal²
¹ Department of Pathology, Malda Medical Centre, Malda, West Bengal, India
² Department of Pathology, Sonoscan Healthcare, Malda, West Bengal, India

Date of Web Publication

12-Oct-2016

Correspondence Address:
Krishnendu Mondal
C/O Barendra Nath Mondal, Vill-Fularhat, P.O. and P.S. Sonarpur, South 24 Parganas - [email protected] 150, West Bengal
India

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DOI: 10.4103/2468-6360.191914

Abstract

Ovarian mature cystic teratoma is a common benign neoplastic condition. Pathogenetically, it arises from all three embryonic layers or any combination thereof. Histologically, it appears as disorganised mass of various tissue components. Rarely, these tissues are orchestrated in an orderly fashion to commence organogenesis and simulate a foetus, namely 'homunculus'. However, isolated organic development, particularly of mesodermal derivation, in an otherwise haphazard teratoma is exceptional. Herein, we discuss a case of mature cystic teratoma with multiple foci of haematopoietic bone marrow within its adipocyte-rich Rokitansky protuberance.

Keywords: Haematopoietic bone marrow, mature cystic teratoma, mesoderm, ovary, Rokitansky protuberance

How to cite this article:
Banik T, Mondal K, Mandal R. Haematopoietic bone marrow: An uncommon mesodermal derivative in mature teratoma. J Health Spec 2016;4:297-300

How to cite this URL:
Banik T, Mondal K, Mandal R. Haematopoietic bone marrow: An uncommon mesodermal derivative in mature teratoma. J Health Spec [serial online] 2016 [cited 2021 Jan 19];4:297-300. Available from: https://www.thejhs.org/text.asp?2016/4/4/297/191914

Introduction

The terminology 'Teratoma' historically originated from Greek word 'Teraton' means 'a monster'. ^[1] Ovary is its most common site of origin. Primarily teratomas are classified as mature, immature and monodermal subtypes. The mature teratoma is the most common ovarian germ cell neoplasm accounting for about 20% of all ovarian neoplasms and 30% of all benign ovarian neoplasms. ^[2],[3] Although mature tissue elements derived from all three germ layers constitute this neoplasm, the ectodermal derivatives usually predominate. ^[3] Keratinising stratified squamous epithelium, adipose tissue and non-specific ductal/glandular formations appear to be the most frequent, whereas uveal tissue, lymphatics and thyroid are the most unusual ectodermal, mesodermal and endodermal components, respectively. Haematopoietic tissue is also an uncommon mesodermal element. Only 0 - 9.5% of mature teratomas develop this component. ^[4],[5] On the other hand, presence of well-developed haematopoietic bone marrow with intercepting osseous trabeculae represents organic development, which has only been described in 'fetiform teratoma' or 'homunculus'. ^[6]

We hereby emphasise an otherwise classical case of mature cystic teratoma without any fetiform changes, which contained multiple circumscribed foci of bone marrow within its Rokitansky protuberance.

Case report

A 35-year-old female was sonologically diagnosed with right ovarian cystic teratoma, after initially complaining about heaviness in lower abdomen over preceding few months. She promptly underwent total oophorectomy under regional anaesthesia, and the specimen was en masse procured for histopathological examination. She was discharged on the fifth postoperative day after experiencing an uneventful recovery.

Grossly, the tumour was well encapsulated and globular in shape. It measured 15 cm × 11 cm × 8 cm with a tense cystic consistency. On cut section, a multiloculated cyst was detected, containing yellowish, thick, fatty, sebaceous material with admixed hair-tangles. A solid 'Rokitansky protuberance' with its hair-bearing surface was attached to the inner cyst wall. On resection, the protuberance mostly consisted of adipose tissue. Multiple tiny brownish foci, rimmed by thin sclerotic shell, were seen on serial-sectioning as punctate areas within the adipose tissue [Figure 1]. Sections from cyst wall and Rokitansky protuberance were microscopically evaluated.

Figure 1: Grossly, multiloculated cystic SOL containing hair and sebaceous material, with multiple brownish foci (arrows) of haematopoietic tissue, surrounded by thin sclerotic rim (inset), within the Rokitansky protuberance

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Histopathologically, the cyst wall was exclusively comprised normal cutaneous structures. Mature adipose tissue, sheathed by normal epidermis, was the chief constituent of the protuberance. Its central brownish foci were identified as classic haematopoietic bone marrow. It was separated from adjacent adipocytes by a mesenchymal rim, formed externally by mature hyaline cartilage and that undergoing enchondral ossification internally into a narrow trabecular network of woven bone. However, the central portion of these foci was devoid of any bony trabeculae [Figure 2]. The adipocytes and haematopoietic precursors existed in almost equal proportions. The haematopoietic element included islands of erythroid precursors and sheets of maturing granulocytes studded with megakaryocytes [Figure 3]a. Their topographic distribution resembled that of normal physiological bone marrow, i.e., paratrabecular granulopoiesis and intertrabecular, perisinusoidal erythropoiesis [Figure 3]b and c. Other noteworthy tissue elements found within the tumour included fibromuscular fascicles and nerve bundles [Figure 3]d. All these tissue components including the bone marrow were categorised under respective germinal derivatives in the final histopathology report.

Figure 2: Microscopically, keratinising stratified squamous epithelium lining the protuberance and mature fibroadipose tissue separate the haematopoietic marrow from its surface (a; H and E, ×40). The sclerotic shell is externally cartilaginous and undergoes endochondral ossification internally to produce bony trabeculae (b; H and E, ×40); that ceased to exist towards centrally (c; H and E, ×100)

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Figure 3: Microscopically, the haematopoietic tissue contains near equal proportion of adipocytes and marrow precursors including megakaryocytes (arrows) (a), perisinusoidal clusters of erythropoiesis (circles) (b) and paratrabecular diffuse granulopoiesis (c) (H and E, ×400). Other mesodermal derivatives are fibromuscular bundles (far left) and nerves (arrowhead) (d) (H and E, ×100)

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Discussion

Teratoma is the most common germ cell tumour of ovary. Its other sites include testis, central nervous system and mediastinum. Children and women in their reproductive years are usually affected, but 25% teratomas arise in postmenopausal women. ^[3] Patients normally present with abdominal pain, heaviness or exceptionally with abdominopelvic swelling and abnormal uterine bleeding. However, 25 - 60% individuals experience an asymptomatic outcome. ^[7] Pre-operative diagnosis of mature teratomas can satisfactorily be accomplished on radiography, depending on the heteroechogenicity exerted by its variegated tissue constituents, especially bone, cartilage and teeth. ^[3] In the discussed report, the patient was in her mid-thirties and complained about lower abdominal heaviness. On routine ultrasonography, the tumour was readily diagnosed as mature cystic teratoma and was subsequently excised under laparotomy.

Mature teratomas almost always feature one or more smooth cysts lined by epidermis with its appendages and filled with hair and sebaceous material. These are also called 'dermoid cyst'. ^[2] Mature solid teratomas do occur rarely but are more often associated with pain and peritoneal glial implants (gliomatosis peritonei). ^[3] Immature teratomas are usually solid, and primitive neuroectodermal tubulo-rosettes are its signature tissue composition. Monodermal teratomas can be struma ovarii, composed entirely of thyroid parenchyma, carcinoids, melanocytic tumours, etc. ^[7] The tumour from the present case was a classic example of ovarian dermoid cyst. Apart from mature elements, no other embryonic tissue could be appreciated therein.

Dermoid cysts often feature one or more rounded -to-fusiform-shaped Rokitansky protuberances protruding into its cavity. Its surface bears the teeth and hair content of the tumour. Internally, the protuberance contains the principal mesodermal and endodermal constituents of teratoma such as fat, bone, cartilage and thyroid gland. ^[3] In the discussed case, a single protuberance was present, which featured a hair-bearing surface in the absence of any tooth. Its cut surface mainly demonstrated adipose tissue with few foci of haematopoietic marrow rimmed by a thin bony-cartilaginous shell.

Ectoderm and mesoderm compose the major part of a teratoma. In 1971, Caruso et al., ^[4] histopathologically examined 305 teratomas and encountered ectodermal, mesodermal and endodermal derivatives in 99.3%, 73.3% and 31.9% cases, respectively. In contrast, endodermal elements were found in only 19% of 42 teratomas sampled by Khan et al., ^[5] though the other two germinal derivatives existed in all lesions. Accordingly, this currently reported tumour was entirely composed of ectodermal tissues such as skin, nerves and mesodermal tissues such as adipose tissue, fibrous tissue, bone, cartilage and bone marrow.

The gross complexity of teratomas principally depends on its mesodermal composition. ^[8] Moreover, the variation in mesodermal derivatives is much higher than other germinal constituents. ^[5] Adipose tissue, cartilage and bone are the common mesenchymal tissue found in about 66.7 - 78.6%, 21.4 - 38.6% and 11.9 - 18.6% teratomas, respectively. Lymphatics and myxoid tissue are the least reported mesodermal tissue. Haematopoietic tissue is also a relatively secluded mesodermal constituent. ^[4],[5] It predominantly occurs as isolated aggregate of haematopoietic precursors or as lymphoid tissue underlying pharyngeal, respiratory or gastrointestinal mucosa. Well-formed spleen, lymph node or trabecular bone marrow develops on extremely rare occasions. ^[9] Such differentiation and maturation of tissue elements signify organogenesis in teratomas, which has only been described in handful reports of 'homunculus'. ^[6] Individual organic involution in an otherwise disorderly teratoma has been documented with skin, mandible and bronchus. ^[3],[4] However, even after diligent search, the distinct presence of characteristic haematopoietic bone marrow as recognised in the discussed report, could not be retrieved from already-published literatures regarding mature teratomas.

Finally, to conclude, the three germinal derivatives in a mature cystic teratoma may occasionally get properly oriented. This leads to the organic development within a foetus-like structure, i.e. homunculus. However, the mere presence of an isolated organ, such as the haematopoietic bone marrow, within an otherwise mature teratoma is largely infrequent. A detailed search of teratomas for such organogenesis and their scrutinising histopathological evaluation may unfold some new dimensions regarding embryogenesis or even parthenogenesis in future.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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