Journal of Cancer Research and Practice

CASE REPORT
Year
: 2021  |  Volume : 8  |  Issue : 4  |  Page : 166--168

Light chain myeloma presenting as chronic diarrhea


Mansoor C Abdulla 
 Department of General Medicine, M.E.S. Medical College, Perinthalmanna, Kerala, India

Correspondence Address:
Prof. Mansoor C Abdulla
Department of General Medicine, M.E.S. Medical College, Perinthalmanna - 679 338, Kerala
India

Abstract

Light chain myeloma represents one-fifth of all cases of myeloma and light chain amyloidosis is associated with 10% of cases of myeloma. Multiple myeloma is a plasma cell disorder with diverse presentations. Here, we present a 72-year-old male with light chain myeloma with colorectal amyloidosis. Chronic diarrhea secondary to isolated colorectal amyloidosis as an initial presentation of multiple myeloma is extremely rare. Early diagnosis is important for timely therapeutic interventions which can improve the treatment outcome in this otherwise uniformly fatal disease.



How to cite this article:
Abdulla MC. Light chain myeloma presenting as chronic diarrhea.J Cancer Res Pract 2021;8:166-168


How to cite this URL:
Abdulla MC. Light chain myeloma presenting as chronic diarrhea. J Cancer Res Pract [serial online] 2021 [cited 2022 May 26 ];8:166-168
Available from: https://www.ejcrp.org/text.asp?2021/8/4/166/331648


Full Text



 Introduction



Light chain myeloma represents one-fifth of all cases of myeloma, and light chain amyloidosis is associated with 10% of cases of myeloma. Extracellular deposition of immunoglobulin light chain fibrillin major organs such as the kidneys, heart, and bowel can be seen. Isolated gastrointestinal amyloidosis is rare. Chronic diarrhea as an initial presentation of light chain myeloma is unusual.

 Case Report



A 72-year-old male presented with loose stools for 2 years. The stool was small in volume, 3–4 episodes per day, watery, and not foul smelling. He had a history of blood in stools for the last 1½ years and had a significant loss of weight (65–53 kg) in the past 6 months. He had stopped smoking 30 years previously and had no other addictions. He was poorly nourished and had moderate pallor. A neurological examination showed bilateral symmetrical sensorimotor peripheral neuropathy of the lower limbs. The rest of the systemic examination was normal.

Hemoglobin was 9.8g/dl (normocytic and normochromic), total leukocyte count was 8000/ml (88% neutrophils, 10% lymphocytes, and 2% monocytes), platelet count was 200,000/μl, and the erythrocyte sedimentation rate was 22 mm in 1 h. Peripheral smear showed normocytic normochromic anemia without any atypical cells. Biochemical tests showed normal blood sugar level, liver function, renal function, and electrolytes. Chest X-ray and electrocardiogram were normal. A stool examination revealed few red blood cells and no larvae or cysts. A stool culture was sterile. Contrast-enhanced computerized tomography showed long segment circumferential thickening of the entire colon. Colonoscopy showed multiple discrete large white-based superficial ulcers with surrounding mucosal edema and erythema in the rectum, sigmoid transverse, and ascending colon. A nerve conduction study showed axonal polyneuropathy of all four limbs. A histological examination of a colonic biopsy showed deposition of amorphous eosinophilic material stained positively with Congo red stain in the lamina propria, showing apple-green birefringence under polarizing light [Figure 1] and [Figure 2].{Figure 1}{Figure 2}

A bone marrow biopsy showed 60% of plasma cells with lambda restriction [Figure 3]. Urinary Bence-Jones protein was negative, and serum protein electrophoresis was normal. Free light chain assay showed a κ chain concentration of 14.6 mg/L (3.3–19.4 mg/L), λ chain concentration of 1290 mg/L (5.7–26.6 mg/L), and aκ/λ ratio of 0.011 (range 0.26–1.75). The elevated λ chain concentration with normal κ chain concentration and low κ/λ ratio suggested light chain myeloma. A diagnosis of light chain myeloma with primary amyloid light chain (AL) amyloidosis was made, and the patient was started on chemotherapy with dexamethasone and bortezomib.{Figure 3}

 Discussion



Chronic inflammatory diarrhea can be secondary to inflammatory bowel disease, diverticulitis, invasive infections, and malignancy. Gastrointestinal amyloidosis is a rare cause of chronic diarrhea which can be diagnosed correctly by histopathological examination. Gastrointestinal amyloidosis causes amyloid deposition in the muscularis mucosa close to vasculature, nerves, and nerve plexuses.[1] This can result in altered peristalsis and damage to blood vessels, resulting in clinical manifestations of gastrointestinal amyloidosis.[2] The most common site of gastrointestinal amyloidosis is the small intestine.[3] Amyloid of the colon is most frequently located in the descending and rectosigmoid colon. The clinical manifestations in the colon may mimic other diseases such as inflammatory bowel disease, malignancy, ischemic colitis, and at times collagenous colitis. Endoscopic and radiologic findings of gastrointestinal amyloidosis are nonspecific. Isolated gastrointestinal amyloidosis is rare.[4]

Light chain myeloma is a subtype of multiple myeloma characterized by the production of only light chains, and it accounts for approximately 15%–20% of all multiple myeloma patients.[5] AL amyloidosis refers to immunoglobulin light chain deposition commonly associated with plasma cell dyscrasias such as multiple myeloma. The concentration of immunoglobulin light chains is important; the long-term risk of developing AL amyloidosis in patients with monoclonal gammopathy of undetermined significance is estimated to be 0.8%, whereas the risk associated with multiple myeloma is 38%.[6] Amyloid deposition in the muscularis mucosae, submucosa, muscularis propria, and their vessel walls is dominant in AL amyloidosis, resulting in polypoid protrusions, thickening of valvulae conniventes, multiple bullous hemorrhagic lesions, submucosal hematomas, mucosal ulcerations, and submucosal hemorrhages.[7] The symptoms include chronic diarrhea, stasis symptoms such as vomiting, nausea, gastrointestinal reflux, constipation, or even chronic intestinal pseudo-obstruction.[8] However, only 30–60% of affected individuals develop symptoms from the disease.

 Conclusions



Gastrointestinal amyloidosis in patients with chronic diarrhea with other possible signs of systemic amyloidosis such as cardiac or renal involvement and autonomic dysfunction can be diagnosed easily. Our patient had no other manifestations of amyloidosis other than chronic diarrhea to suggest the possibility of systemic amyloidosis. Chronic diarrhea secondary to isolated colorectal amyloidosis as an initial presentation of multiple myeloma is extremely rare. Although amyloidosis with gastrointestinal involvement is a rare cause of chronic diarrhea, it should be considered in the differential diagnosis.

Declaration of patient consent

The author certifies that he has obtained appropriate patient consent form. In the form, the patient has given his consent for the images and other clinical information to be reported in the journal. The patient understands that his name and initial will not be published and due efforts will be made to conceal the identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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