Cutaneous metastasis in anorectal adenocarcinoma.

Cutaneous metastasis in anorectal adenocarcinoma is a rare entity. Here, we report the case of a 40-year-old female who presented with yellowish-brown, irregular, solid, elevated rashes over the pubis with a recent history off palliative colostomy for anorectal adenocarcinoma. Clinically, we suspected metastasis that was proved on biopsy. We report this case due to the rare presenting site (i.e., perineum) of a metastatic adenocarcinoma.

INTRODUCTION

Skin being the largest organ has a high propensity for metastasis for various malignant lesions 0.9%−8%.[1] Lesions may be solitary, multiple, or disseminated. Quite often, cutaneous metastasis is detected as occult malignancy. Common malignancies that metastasize to the skin are breast and gastrointestinal tract in females and lungs in males. Here we present a case of stage IV primary anorectal adenocarcinoma with hepatic metastasis and secondaries in the skin, the latter site being a rare site for large bowel malignancy.

CASE REPORT

A 40-year-old female presented with yellow-brown, irregular, solid, elevated, progressive rashes on the pubic region with a history of excruciating pain and occasional bleeding from the lesions for the since two months. One month prior, she had undergone a palliative colostomy for a biopsy-confirmed anorectal adenocarcinoma. The patient was cachexic. Local examination revealed the involvement of the entire pubic area, labia majora, and medial side of thighs with numerous verrucous nodules which were firm, tender, and inflamed [Figures 1–3]. The per-rectal examination showed a complete circumferential induration of the anal canal with tenderness and active bleeding. Per-vaginal examination revealed sparing of the vaginal urethral vault. The femoral group of lymph nodes was palpable and fixed bilaterally. The colostomy in the right iliac fossa draining into a colostomy bag was healthy. Routine investigations showed hemoglobin of 9.6 g/dL, with normal total leukocyte count, diffenential leukocyte count and platelet count; erythrocyte sedimentation rate was 88 mm/h. Liver and kidney functions were normal. Tests for human immunodeficiency virus and hepatotropic viruses were negative. Histopathology of the lesional skin revealed clusters of cells with atypical acinar structures infiltrating the stroma, with pleomorphic cells showing hyperchromatic nuclei, suggestive of adenocarcinoma [Figures 4 and 5]. Ultrasound and computed tomography (CT) abdomen-pelvis showed two well-marginated liver metastases. There was evidence of concentric anorectal wall thickening, and streaky infiltration.

Figure 1

Firm, tender and inflamed verrucous nodules in the pubic region

Figure 3

Firm, tender and inflamed verrucous nodules over the genitalia and both thighs

Figure 4

Epidermis thinned out but with elongated, thinned and anastomosing rete ridges. Dermis shows tubular, glandular structures with eosionophilic (necrotic) material (Hematoxylin and eosin ×40)

Figure 5

Dermis showing variable sized tubular/glandular structures lined by 2-3 malignant epithelial cells with necrosis in the lumen (Hematoxylin and eosin ×100)

Firm, tender and inflamed verrucous nodules on the thigh

DISCUSSION

Metastasis (meta-transformation and stasis-residence) is defined as “spread of tumor by invasion in such a way that, discontinuous secondary tumor mass/masses are formed at the site of lodgment” (Harsh Mohan). Metastases to the skin are uncommon, occurring in 0.9% to 8% of all patients with underlying malignancies.[12] One study of women with an internal malignancy and cutaneous metastasis reported the breast (69%), the large intestine (9%), malignant melanoma (5%) and carcinoma of the ovary (4%). In men, the most common primary tumors, in order of decreasing frequency, are carcinoma of the lung (24%), large intestine (19%), melanoma (13%) and squamous cell carcinoma of oral cavity (12%).

Cutaneous metastases occur generally within 1 to 2 years of resection of the primary cancer but can occur at any time. Infrequently, cutaneous metastasis can be the presenting symptom of a primary adenocarcinoma.[3] Our female patient had biopsy proven Anorectal Adenocarcinoma with Cutaneous metastasis at the same time.

Systemic metastasis from colonic adenocarcinoma usually spreads to the liver, peritoneum, pelvis, lung and bone in decreasing order of frequency. Besides systemic metastasis certain internal malignancies appear to metastasize to the specific cutaneous sites. Primary lung and breast tumors most often send secondaries to the chest wall and axilla, while rectal carcinoma metastasize to the middle or lower dermis of the abdomen and the perianal skin, usually to the abdominal wall and around the umbilicus; the metastasis also often appear after surgery for rectal carcinoma.[45] While rare, cases have been reported with lesions of the scalp, face, neck, glans penis, surgical scars and distal upper and lower extremities.[67] Our patient presented with perineal metastatic disease with the involvement of the pubic area, labia majora and medial side of thigh. She had cutaneous as well as systemic dissemination of the tumor in the form of two well marginated hepatic metastases. Her hepatic functions had been on the contrary well maintained. An autopsy study of patients with colonic adenocarcinoma revealed metastasis to the skin in less than 4% of all cases.[8] Thus cutaneous metastasis secondary to a primary large bowel malignancy are not as common as theoretically mentioned (in the study above).

The malignant cells may spread by direct extension from the underlying tumour, by dissemination to locoregional sites through lymphatics or by hematogenous dissemination to distant sites or by accidental implantation at surgery. Sparing of the vaginal and urethral vault in our patient ruled out direct spread of the tumor. The dissemination might have occurred through the haematogenus route.

Rectal carcinoma metastasis to the skin has no distinctive characters tics. The lesions most often present as small subcutaneous or intradermal nodules that vary from flesh coloured to brown-black hues. The nodules range from 1cm to 2cm and have a tendency to coalesce as the cancer progresses. They are generally asymptomatic, firm, rubbery and non-painful, with little to no epidermal change. The nodules are almost always stony hard when palpated and rarely ulcerate. Our patient had verrucous nodules, which were firm, tender and inflamed. There was history of occasional bleeding locally. Cutaneous metastases may mimic cysts, lipomas, neurofibromas, granulomas or alopecia.[49] Inflammatory metastatic rectal adenocarcinoma to the skin rarely occurs but has been reported.[10] These cases present initially as a small area of inflammation with a sharply marginated and slightly elevated border. Cellulitis or erysipelas is most often diagnosed only once tumour nodules appear within the erythematous lesion. As such, any unexplained erythema lasting greater than 2 weeks in patients with history of malignancy should be biopsied immediately.[4]

Microscopically the metastases generally mimic the primary tumor. However, in certain cases, the metastasis may show an anaplastic pattern or may be difficult to diagnose.[49] The biopsy of the perineal lesion taken in our department came out to be consistent with the biopsy finding of the primary neoplasm that of adenocarcinoma.

Once the lesion is determined to be of metastatic origin, patients should undergo a vigorous management profile to cure the present disease and to prevent the occurrence of additional metastases at other sites. Patient education plays a major role in this early detection.

Patients with a history of rectal carcinoma should be taught to inspect all areas of their skin several times annually, recognize signs of cutaneous metastasis and know what action should be taken if a questionable lesion is found. It is extremely important that follow up for patients with cancer includes regular dermatological examinations and that the practitioner should be aware of the skin as a potential site of metastasis.[9] Surgical intervention offers little hope but chemotherapy and radiotherapy may help prolong survival. The response of cutaneous metastatic disease to chemo therapy or radiotherapy, mirrors the response of the primary tumor, hence is helpful in evaluation of the efficacy of the therapy. Our patient had been posted for chemotherapy with Leucovarin and 5-flurouracil, but the patient refused to take it.

Because cutaneous metastasis from primary malignant lesions is most often an ominous sign indicative of wide spread, terminal disease, prognosis is generally poor and the treatment for the majority of patients is palliative.[7] may help prolong survival. The survival period following diagnosis of cutaneous rectal metastasis is 1-34 months.[1112] Our patient expired within 5 month of the diagnosis of her metastatic disease.

CONCLUSION

The idea of reporting this case is metastasis to the skin of the perineum is rare. Apart from anorectal biopsy which was reported as adenocarcinoma, the skin biopsy which was taken in our department also gave the finding suggestive of adenocarcinoma.