|LETTER TO THE EDITOR
|Ahead of print
Renal hypodysplasia with epididymis-like tubules presenting as renal cancer: An unusual finding at nephron-sparing surgery
Subhash C Yadav1, Santosh Menon1, Sangeeta Desai1, Palak Popat2
1 Department of Surgical Pathology, Tata Memorial Hospital, Homi Bhabha National Institute, Mumbai, Maharashtra, India
2 Department of Radiodiagnosis, Tata Memorial Hospital, Homi Bhabha National Institute, Mumbai, Maharashtra, India
|Date of Submission||16-Apr-2019|
|Date of Decision||22-Jul-2019|
|Date of Acceptance||04-Aug-2019|
|Date of Web Publication||05-Aug-2020|
Department of Surgical Pathology, Tata Memorial Hospital, Homi Bhabha National Institute, Mumbai, Maharashtra
Source of Support: None, Conflict of Interest: None
|How to cite this URL:|
Yadav SC, Menon S, Desai S, Popat P. Renal hypodysplasia with epididymis-like tubules presenting as renal cancer: An unusual finding at nephron-sparing surgery. Indian J Cancer [Epub ahead of print] [cited 2020 Sep 28]. Available from: http://www.indianjcancer.com/preprintarticle.asp?id=291410
A 29-year-old man, treated case of acute promyelocytic leukemia low risk, on follow-up came with complaints of right-sided abdominal pain. Ultrasonography (USG) revealed a well-defined cystic lesion with scalloping of the renal vessels in the right kidney. A contrast enhanced computed tomography (CECT) scan revealed a well-defined heterogeneously enhancing solid-cystic lesion in the upper and mid-pole of right kidney measuring 2.5 × 2.7 cm, suggestive of a malignant renal neoplasm [Figure 1]. Initial biopsy performed comprised only normal renal parenchyma on histology. Hence, an open nephron sparing surgery was planned. Grossly, the specimen measured 4 × 3.5 × 3.1 cm and on cut surface, had a solid-cystic lesion with focal yellowish areas. Microscopy showed many dilated tubules, some with stellate lumen lined by ciliated columnar epithelium with clear to pale eosinophilic cytoplasm and a distinct cellular smooth muscle coat around them resembling epididymis. Cartilage, squamous epithelium, mucinous lining, glial tissue, renal blastema, undifferentiated mesenchyme, immature collecting ducts, and primitive glomerular structures were not seen, even after completely embedding the tissue, thereby ruling out a renal teratoma and cystic Wilms tumor. Cellular atypia/dysplasia was not identified [Figure 2]a, [Figure 2]b, [Figure 2]c, [Figure 2]d, [Figure 2]e. On immunohistochemistry (IHC), the tubular epithelium comprised of a dual lining with luminal PAX-8 antibody positive epithelial cells and p40 antibody positive basal epithelial cells. CD10 antibody stained the luminal membrane of the epididymis-like tubules highlighting the ciliated border. CK7 antibody showed cytoplasmic staining of both luminal and basal cell. The surrounding smooth muscle proliferation was strongly positive for smooth muscle antigen (SMA), estrogen receptor (ER), and progesterone receptor (PR). The epithelium (both luminal and basal cells) were also positive for GATA-3, ER, and PR. [Figure 3]a, [Figure 3]b, [Figure 3]c, [Figure 3]d The histomorphology with supportive immunoprofile clinched the diagnosis as a renal hypodysplasia with presence of epididymis-like tubules. Patient is on regular follow-up for 17 months and is doing well without any complaints.
|Figure 1: CECT showed a well-defined heterogeneously enhancing lesion in the mid-pole of right kidney measuring 2.5 × 2.7 cm with few specks of calcification and cystic areas|
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|Figure 2: (a-c) Dilated tubules lined by luminal ciliated columnar epithelium with clear to pale eosinophilic cytoplasm and basal cells with a distinct cellular spindle cell proliferation around them resembling epididymis. (d) CK7 showing cytoplasmic staining of both luminal and basal cells of the tubules. (e) PAX-8 showing nuclear staining of the luminal epithelium|
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|Figure 3: (a) CD10 highlights the luminal membrane. (b) SMA highlights the smooth muscle coat around the tubules. (c-d) ER and PR stains the epithelium as well as the surrounding smooth muscle proliferation|
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Dysplastic kidneys are not uncommon, but presence of epididymis-like tubules in them is rare. There have been very few case reports which describes dysplastic kidney containing tubules lined by ciliated tall columnar epithelium surrounded by fibromuscular coat. Till now only 26 cases of renal dysplasia with epididymis-like tubules have been reported in the literature, majority being case reports., Most authors believe this to be of mesonephric origin based on their dichotomous branching, communication with calyceal system and absence of associated glomeruli, which are metanephric in origin. As per Naik and Pai, ER was negative in the epithelium and smooth muscles of the tubules in their cases. In contrast, Magerset al. demonstrated strong ER and PR coexpression in the epididymal appendages in the adults The morphology and immunoprofile of these tubules is therefore like epididymis which are mesonephric in origin, further supporting a mesonephric origin for these tubules, probably as a result of aberrant renal genesis.
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.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]