Australian Society of CytologyCase of the Month
October 2004 - Answer and Discussion
Metastatic adenocarcinoma, rectal origin
Answer
Cytology:
The smear is heavily blood stained with an inflammatory and necrotic background. There are numerous abnormal cells showing high N/C ratio, scanty cytoplasm, crowded and overlapping nuclei with coarse granular chromatin, hyperchromasia and nucleoli. The abnormal cells are long columnar in shape with occasional palisading edges, some feathering and acinar formation. Bare elongated nuclei are not uncommon.
Cytology Diagnosis:
The features are consistent with Adenocarcinoma (unspecified).
Cervical Biopsy:
Extra clinical history of existing sigmoid colon adenocarcinoma was given. At the time of biopsy, cervix looked definitely malignant grossly. Biopsy showed extensive necrosis within and surrounding the tumour. Histological features are consistent with adenocarcinoma and suggestive of rectal origin.
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Immunohistochemistry:
Cytokeratins (CK7 and CK20) were used and the result showed CK7 negative and CK20 focal but definitely positive in cancer cells.
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Profiles |
Primary sites |
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CK7+ CK20- |
Lung adeno(74%), breast(84%), ovarian serous(100%), endomet(80%), pancreas(26-85%), cholangioCA(75%), gallbladder(60%) |
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CK7+ CK20+ |
Urothelial (89%), pancreatic(65%), ovarian mucinous |
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CK7- CK20+ |
Colorectal adenoCA(75%) Gastric(35%), pancreas(9%), renal (6%), breast ductal CA(3%) |
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CK7- CK20- |
Hepatoma(77%), renal cell(71%), prostatic(62%), lung sq CA(92%) |
Further investigation:
Slides from original sigmoid colon adenocarcinoma retrieved from RPAH reviewed and compared with the cervical biopsy. They showed similar morphology.
Conclusion:
Metastatic adenocarcinoma, rectal origin
Discussion
Extrauterine tumours found in cervix and vagina are usually of glandular type and only rarely of squamous type, melanoma, sarcoma, lymphoid or leukemic cell type.
Factors affecting the shedding of malignant cells into the cervix / vagina include the site of primary tumour (distance from the cervix and tendency to spread), extent and location of spread (direct spread in pelvic tumours), presence of ascites and patency of the uterine tubes.
Primary sites most commonly come from ovary (60%) and gastrointestinal (colon) region and less frequently from uterine tube, pancreas, urethra, breast and abdominal mesothelium. Melanoma had been documented. Rare primaries include the lung, urinary bladder, gallbladder and appendix. Choriocarcinoma has relatively high rate of cervical metastasis and distant primary sites (eg gastrointestinal tract and breast) foci are rare.
Characteristics of metastatic cancers in cervix include clinical history of treated or untreated cancer of neighbouring organ (metastasis may occur primarily as cervical involvement and pose a differential diagnostic problem), ascites and lack of tumour diathesis (80%) in general (less than 10% of endometrial & less than 15% of endocervical carcinoma lack diathesis). Less than 20% have a diathesis with mucosal involvement & ulceration seen, in many cases not conspicuous (exception-rectal cancer). The cellular morphology may give a hint for it's metastatic nature.
Colorectal cancer shows specific cellular features. Nuclei have elongated (cigar-like) contour and was named needle cells by Thabet & MacFarlane. Chromatin is finely to moderately granular and hyperchromatic with one or more nucleoli. Cytoplasm is inconspicuous but at times mucin vacuoles are evident. Crowded nuclei may form palisades and be irregularly overlapped. The background is characterised by extensive necrosis.
Endocervical adenocarcinoma and rectal cancer may mimic each other. The latter tends to have more granular and coarser chromatin. (June 04 issue of Cytoletter)
As far as rectal cancer is concerned, it more commonly spreads to liver, lung and lymph nodes but rarely spreads to the cervix. The reasons behind are the high fibrous content of the cervix, and as a small organ with limited blood supply, it's an unfavourable place for tumour growth. Also the lymphatic vessels in the pelvic region drain away from the uterus. Last but not least failure to diagnose secondary rectal cancer / misdiagnosed as cervical primary and sometimes cervix is simply not screened for secondary spread.
Further confirmation tests / investigations include colon biopsy and endoscopic brush (considered more sensitive than colon biopsy).
Summary:
In conclusion, a case of metastatic rectal cancer in the cervix is presented. The main features for the cancer include extensive necrotic background and extremely elongation of malignant columnar cells. Patient's clinical history can be crucial but unfortunately wasn't given at the time of cytology diagnosis. Cytokeratins CK7 and CK20 can be used for confirmation of primary site in biopsy.
References:
- Immunohistochemistry in Carcinoma (T. Miller M.D.)
- Japanese Journal of Clinical Oncology (Nakagami et al)
