Metastatic Tumors to the Skin



Metastatic Tumors to the Skin


Christine J. Ko, MD

David Cassarino, MD, PhD





Key Facts


Clinical Issues



  • Cutaneous metastases often located near primary tumor site


  • Incidence rate of ˜ 2-10% in patients with internal malignancy


  • Breast cancer metastasizes to skin most frequently


  • In most cases, skin metastases present after primary tumor has been diagnosed


  • Very poor prognosis


Microscopic Pathology



  • Many metastases represent adenocarcinoma



    • Irregular collections of cells, often with lumina


Ancillary Tests



  • “Organ-specific” markers include PSA, TTF-1, CDX-2, and RCC


  • Cytokeratin 7 (CK7) and cytokeratin 20 (CK20)



    • Traditionally, these stains helpful in narrowing down origin of metastatic carcinoma


  • Cytokeratin 5/6, p63, podoplanin/D2-40



    • Positivity with these stains supports a primary cutaneous origin over a metastasis


Top Differential Diagnoses



  • Metastatic adenocarcinoma



    • Primary adnexal tumors of skin: Generally positive with p63, cytokeratin 5/6, podoplanin


  • Metastatic renal cell carcinoma



    • Clear cell hidradenoma and hidradenocarcinoma


  • Metastatic small cell carcinoma of the lung



    • Main differential is with primary cutaneous Merkel cell carcinoma







This patient presented with a pink nodule on the anterior scalp. Certain tumors, like renal cell carcinoma (RCC), have the tendency to metastasize to the scalp.






This low-power image shows collections of clear cells with pools of extravasated erythrocytes, consistent with metastatic RCC. These tumors are typically positive with CD10, EMA, and RCC-Ma.


ETIOLOGY/PATHOGENESIS


Mode of Metastasis



  • Hematogenous spread


  • Lymphatic spread


  • Direct extension from primary tumor


  • Accidental implantation during surgical procedure



    • Described with oral cavity, laryngeal, lung, mesothelioma, renal cell, colorectal cancers and others


CLINICAL ISSUES


Epidemiology



  • Gender



    • Male: Primary tumor most often lung, colon


    • Female: Primary tumor most often breast, colon


Site



  • Cutaneous metastases often located near primary tumor site



    • Breast carcinoma: Chest wall


    • Lung carcinoma: Chest wall


    • Genitourinary carcinoma: Abdominal wall, rarely genitalia


    • Oral cavity: Head and neck


  • Scalp



    • Tumors with a predilection to metastasize to scalp



      • Thyroid


      • Breast


      • Kidney


      • Lung


  • Umbilicus: Sister Mary Joseph nodule



    • Associated with adenocarcinoma of stomach, pancreas, ovary, and others


Presentation



  • General points



    • Incidence rate of ˜ 2-10% in patients with internal malignancy


    • Rare among skin tumors (˜ 2% of all skin tumors)


    • Patients generally of age 60 or above, but exceptions occur



      • In neonates, neuroblastoma or other small round blue cell tumors may metastasize to skin


    • Skin metastases usually present within 2-3 years of diagnosis of primary


    • Breast cancer metastasizes to skin most frequently


    • Other internal cancers with not infrequent skin metastases include lung, colorectal, ovarian, head and neck, renal cell carcinoma, and gastrointestinal cancer


  • Signs/symptoms



    • Appearance



      • Generally red-pink, 1-3 cm firm nodule


      • Deeper purple or “vascular” appearance has been described for renal cell carcinoma metastasis


      • Multiple or solitary


      • Clustered or randomly distributed


      • May be movable or fixed, sometimes ulcerated


      • Uncommon bullous or inflammatory patterns of metastasis


    • Asymptomatic or painful


  • Special clinical variants



    • Inflammatory (erysipeloid) carcinoma



      • Lymphatic spread of carcinoma


      • Warm, red, tender plaque; resembles erysipelas


      • Most commonly associated with breast carcinoma, but also may be due to other carcinomas (i.e., colon, prostate) and melanoma


    • Carcinoma telangiectoides



      • Secondary to breast carcinoma


      • Plaque of coalescing telangiectasias and erythematous papules


    • Carcinoma en cuirasse



      • Secondary to breast carcinoma


      • Skin hardened and leathery


    • Superior vena cava syndrome




      • Can be secondary to lung carcinoma


      • Obstruction of superior vena cava leads to edema, cyanosis, plethora of head/neck; subcutaneous vessels may be prominent


    • Sister Mary Joseph nodule



      • Classically described as red nodule on umbilicus, most commonly due to gastric carcinoma


    • Alopecia neoplastica



      • Localized patches of alopecia on scalp secondary to metastatic disease in dermis


Laboratory Tests



  • Ovarian cancer



    • High CA-125 suggestive of advanced disease


    • CA 19-9 may be elevated


  • Colon cancer



    • CEA may be used to monitor disease


  • Hepatocellular and testicular cancer (and some others)



    • α-fetoprotein may be elevated


  • Pancreatic cancer



    • CA 19-9 may be elevated


  • Gastric cancer



    • CA 19-9 may be elevated


  • Prostate cancer



    • Prostate-specific antigen (PSA) often elevated


Natural History



  • Skin metastases are rarely presenting clue to internal malignancy


  • In most cases, skin metastases present after primary tumor has been diagnosed


Treatment



  • In advanced disease, excision of metastases may be palliative


  • Other treatment options dependent on type of tumor and extent of disease (e.g., chemotherapy or radiation)



    • Chemotherapy



      • Traditional drugs (e.g., anthracyclines, taxanes)


      • Trend is to test tissue for molecular targets, and if positive, use targeted treatment (e.g., trastuzumab in Her2-neu positive breast cancer, tamoxifen in estrogen receptor positive cancers)


Prognosis



  • Poor overall survival



    • One study cites range of 1-34 months


MICROSCOPIC PATHOLOGY


Histologic Features

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Jul 8, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Metastatic Tumors to the Skin

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