Cutaneous metastatic adenocarcinoma

Case Report

A 55-year-old male, farmer, chronic smoker for many years presented with 6 asymptomatic nodules and plaques on scalp and pubic region of 2 months duration. The lesions had appeared spontaneously and enlarged rapidly. He gave history of cough, haemoptysis, chest pain, anorexia and weight loss for last 4 months. He was being treated with anti-tuberculosis drugs for these symptoms for the last 3 months. He gave no past or family history of tuberculosis, diabetes or hypertension. He was emaciated and had pallor. There was no icterus, cyanosis, clubbing, pedal edema or lymphadenopathy. Chest examination revealed decreased breath sounds in both upper zones and right middle zone. There was no hepatosplenomegaly or ascites. Per-rectal examination was normal. Cutaneous examination revealed 4, well-defined, skin-coloured and erythematous, firm, non-tender, 0.5-4.0cm nodules over scalp [Figure - 1] and a single well defined, irregular plaque studded with firm papules in the pubic region. Clinical diagnosis of secondaries in the skin with a primary malignancy of the lung was made.

Investigations revealed anemia and hyperuricemia (serum uric acid: 8.9mg/dl; Normal= 2.5-7.Omg/dl). Liver and kidney function tests, urinalysis and stool examination were norml. Chest x-ray revealed multiple, round, coin shaped shadows in the right upper, middle and lower and left middle zones along with right sided pleural effusion. Skeletal survey of long bones, spine and pelvis was normal. Scalpel biopsies from one of the nodules on scalp and from the pubic region showed multiple islands of tumour cells forming ill defined nodules lying in the upper and lower dermis. On high power examination, pleomorphic tumour cells forming glands and having prominent nucleoli and frequent mitoses were seen. The features were those of metastatic adenocarcinoma of the skin. Ultrasound of abdomen was normal. For further staging and definitive diagnosis of the primary, the patient was advised to undergo whole body CT scan and bronchoscopic biopsy from the lung which he refused. The patient decided to go for the alternative system of medicine and was lost to follow-up.

Discussion

Cutaneous metastases occur in 0.7% to 9.0% of all patients with cancers.[1] Skin metastases were the first sign of extranodal disease in 7.6% of cancer patients.[2] Incidence of various tumours metastasizing to the skin correlate with the sex-wise frequency of occurrence of various primary malignancies.[1] Breast carcinoma (69%) is the commonest cause of cutaneous metastases in women followed by carcinoma of the large intestine (9%), lungs and ovaries (4%).[3] The primary sites of carcinoma with cutaneous metastases among men in decreasing order are lungs (24%), large intestine (19%), oral cavity (12%), kidney and stomach (6% each).[3] Cutaneous metastases as the first sign of internal malignancy are seen most frequently with carcinoma of the lung, kidney and ovary.[4]

Dissemination occurs through lymphatics or haematogenously.[3] When it occurs through lymphatics, there is involvement of the overlying skin as seen in cancers of the breast and oral cavity. Hematogenous spread as seen in other cancers may cause lesions anywhere in the skin. Most cutaneous metastases arise as non-specific, painless, dermal or subcutaneous nodules with an intact overlying epidermis.[4] Most common pattern is clusters of discrete, firm, painless nodules emerging rapidly, proliferating swiftly and then remainig stationary. Occasionally the lesions may be zosteriform or inflammatory. Growth pattern of skin metastases is unpredictable and may not reflect that of the primary tumour. Abdominal wall is the most common site for tumours presenting as cutaneous metastatic disease with carcinoma lung being the most frequent cause. Metastases of cancer of lung is more common in men but the incidence of this cancer in women is also rising. The lesions present as clusters of papules or nodules or sometimes a solitary nodule. Commonest sites are the chest wall, back and scalp.[4] In a study by Brady et al, 7% patients were found to have a skin nodule before diagnosis of the primary lung tumour and 16% had cutaneous metastases at the time of diagnosis.[5] The skin was the first extranodal site of metastasis in 11 out of 21 patients.[6] Cutaneous metastases due to lung cancer are of undifferentiated type in 4°ro and adenocarcinomatous and squamous cell carcinoma type in 3% each.[7] Prognosis of patients with cutaneous metastases is not always hopeless because of advancement in cancer treatment but patients of cancer lung with cutaneous metastases still have a poor prognosis.[4]

We are reporting this case to highlight the importance of cutaneous metastases as a presenting sign of internal malignancy. Such metastases offer an easily accessible tissue sample for rapid histopathological diagnosis of the malignancy. They can be an important presenting feature of a recurrence after successful therapy of the internal malignancy. Discovery of cutaneous metastases may alter the staging of an internal malignancy and hence prognosis for a patient. A thorough clinical examination of the skin for any metastasis is mandatory for a patient with any type of cancer.